diff --git a/database.sql b/database.sql
index 9afb7cb0f..60dca5f5f 100644
--- a/database.sql
+++ b/database.sql
@@ -1,6 +1,6 @@
 -- ------------------------------------------
 -- Friendica 2021.03-dev (Red Hot Poker)
--- DB_UPDATE_VERSION 1396
+-- DB_UPDATE_VERSION 1397
 -- ------------------------------------------
 
 
@@ -684,7 +684,6 @@ CREATE TABLE IF NOT EXISTS `item` (
 	`guid` varchar(255) NOT NULL DEFAULT '' COMMENT 'A unique identifier for this item',
 	`uri` varchar(255) NOT NULL DEFAULT '' COMMENT '',
 	`uri-id` int unsigned COMMENT 'Id of the item-uri table entry that contains the item uri',
-	`uri-hash` varchar(80) NOT NULL DEFAULT '' COMMENT 'RIPEMD-128 hash from uri',
 	`parent` int unsigned COMMENT 'item.id of the parent to this item if it is a reply of some form; otherwise this must be set to the id of this item',
 	`parent-uri` varchar(255) NOT NULL DEFAULT '' COMMENT 'uri of the top-level parent to this item',
 	`parent-uri-id` int unsigned COMMENT 'Id of the item-uri table that contains the top-level parent uri',
@@ -710,16 +709,19 @@ CREATE TABLE IF NOT EXISTS `item` (
 	`deleted` boolean NOT NULL DEFAULT '0' COMMENT 'item has been deleted',
 	`uid` mediumint unsigned NOT NULL DEFAULT 0 COMMENT 'Owner id which owns this copy of the item',
 	`contact-id` int unsigned NOT NULL DEFAULT 0 COMMENT 'contact.id',
-	`wall` boolean NOT NULL DEFAULT '0' COMMENT 'This item was posted to the wall of uid',
-	`origin` boolean NOT NULL DEFAULT '0' COMMENT 'item originated at this site',
-	`pubmail` boolean NOT NULL DEFAULT '0' COMMENT '',
-	`starred` boolean NOT NULL DEFAULT '0' COMMENT 'item has been favourited',
 	`unseen` boolean NOT NULL DEFAULT '1' COMMENT 'item has not been seen',
-	`mention` boolean NOT NULL DEFAULT '0' COMMENT 'The owner of this item was mentioned in it',
-	`forum_mode` tinyint unsigned NOT NULL DEFAULT 0 COMMENT '',
+	`origin` boolean NOT NULL DEFAULT '0' COMMENT 'item originated at this site',
 	`psid` int unsigned COMMENT 'ID of the permission set of this post',
-	`resource-id` varchar(32) NOT NULL DEFAULT '' COMMENT 'Used to link other tables to items, it identifies the linked resource (e.g. photo) and if set must also set resource_type',
+	`starred` boolean NOT NULL DEFAULT '0' COMMENT 'item has been favourited',
+	`wall` boolean NOT NULL DEFAULT '0' COMMENT 'This item was posted to the wall of uid',
+	`pubmail` boolean NOT NULL DEFAULT '0' COMMENT '',
+	`forum_mode` tinyint unsigned NOT NULL DEFAULT 0 COMMENT '',
 	`event-id` int unsigned COMMENT 'Used to link to the event.id',
+	`type` varchar(20) COMMENT '',
+	`bookmark` boolean COMMENT '',
+	`mention` boolean NOT NULL DEFAULT '0' COMMENT 'The owner of this item was mentioned in it',
+	`resource-id` varchar(32) COMMENT 'Deprecated',
+	`uri-hash` varchar(80) COMMENT 'Deprecated',
 	`iaid` int unsigned COMMENT 'Deprecated',
 	`icid` int unsigned COMMENT 'Deprecated',
 	`attach` mediumtext COMMENT 'Deprecated',
@@ -729,8 +731,6 @@ CREATE TABLE IF NOT EXISTS `item` (
 	`deny_gid` mediumtext COMMENT 'Deprecated',
 	`postopts` text COMMENT 'Deprecated',
 	`inform` mediumtext COMMENT 'Deprecated',
-	`type` varchar(20) COMMENT 'Deprecated',
-	`bookmark` boolean COMMENT 'Deprecated',
 	`file` mediumtext COMMENT 'Deprecated',
 	`location` varchar(255) COMMENT 'Deprecated',
 	`coord` varchar(255) COMMENT 'Deprecated',
@@ -970,22 +970,6 @@ CREATE TABLE IF NOT EXISTS `parsed_url` (
 	 INDEX `created` (`created`)
 ) DEFAULT COLLATE utf8mb4_general_ci COMMENT='cache for \'parse_url\' queries';
 
---
--- TABLE participation
---
-CREATE TABLE IF NOT EXISTS `participation` (
-	`iid` int unsigned NOT NULL COMMENT '',
-	`server` varchar(60) NOT NULL COMMENT '',
-	`cid` int unsigned NOT NULL COMMENT '',
-	`fid` int unsigned NOT NULL COMMENT '',
-	 PRIMARY KEY(`iid`,`server`),
-	 INDEX `cid` (`cid`),
-	 INDEX `fid` (`fid`),
-	FOREIGN KEY (`iid`) REFERENCES `item` (`id`) ON UPDATE RESTRICT ON DELETE CASCADE,
-	FOREIGN KEY (`cid`) REFERENCES `contact` (`id`) ON UPDATE RESTRICT ON DELETE CASCADE,
-	FOREIGN KEY (`fid`) REFERENCES `fcontact` (`id`) ON UPDATE RESTRICT ON DELETE CASCADE
-) DEFAULT COLLATE utf8mb4_general_ci COMMENT='Storage for participation messages from Diaspora';
-
 --
 -- TABLE pconfig
 --
@@ -1141,6 +1125,26 @@ CREATE TABLE IF NOT EXISTS `post-tag` (
 	FOREIGN KEY (`cid`) REFERENCES `contact` (`id`) ON UPDATE RESTRICT ON DELETE RESTRICT
 ) DEFAULT COLLATE utf8mb4_general_ci COMMENT='post relation to tags';
 
+--
+-- TABLE post-thread-user
+--
+CREATE TABLE IF NOT EXISTS `post-thread-user` (
+	`uri-id` int unsigned NOT NULL COMMENT 'Id of the item-uri table entry that contains the item uri',
+	`uid` mediumint unsigned NOT NULL DEFAULT 0 COMMENT 'Owner id which owns this copy of the item',
+	`pinned` boolean NOT NULL DEFAULT '0' COMMENT 'The thread is pinned on the profile page',
+	`starred` boolean NOT NULL DEFAULT '0' COMMENT '',
+	`ignored` boolean NOT NULL DEFAULT '0' COMMENT 'Ignore updates for this thread',
+	`wall` boolean NOT NULL DEFAULT '0' COMMENT 'This item was posted to the wall of uid',
+	`pubmail` boolean NOT NULL DEFAULT '0' COMMENT '',
+	`forum_mode` tinyint unsigned NOT NULL DEFAULT 0 COMMENT '',
+	 PRIMARY KEY(`uid`,`uri-id`),
+	 INDEX `uid_wall` (`uid`,`wall`),
+	 INDEX `uid_pinned` (`uid`,`pinned`),
+	 INDEX `uri-id` (`uri-id`),
+	FOREIGN KEY (`uri-id`) REFERENCES `item-uri` (`id`) ON UPDATE RESTRICT ON DELETE CASCADE,
+	FOREIGN KEY (`uid`) REFERENCES `user` (`uid`) ON UPDATE RESTRICT ON DELETE CASCADE
+) DEFAULT COLLATE utf8mb4_general_ci COMMENT='Thread related data per user';
+
 --
 -- TABLE post-user
 --
@@ -1166,6 +1170,19 @@ CREATE TABLE IF NOT EXISTS `post-user` (
 	FOREIGN KEY (`psid`) REFERENCES `permissionset` (`id`) ON UPDATE RESTRICT ON DELETE RESTRICT
 ) DEFAULT COLLATE utf8mb4_general_ci COMMENT='User specific post data';
 
+--
+-- TABLE post-user-notification
+--
+CREATE TABLE IF NOT EXISTS `post-user-notification` (
+	`uri-id` int unsigned NOT NULL COMMENT 'Id of the item-uri table entry that contains the item uri',
+	`uid` mediumint unsigned NOT NULL COMMENT 'Owner id which owns this copy of the item',
+	`notification-type` tinyint unsigned NOT NULL DEFAULT 0 COMMENT '',
+	 PRIMARY KEY(`uid`,`uri-id`),
+	 INDEX `uri-id` (`uri-id`),
+	FOREIGN KEY (`uri-id`) REFERENCES `item-uri` (`id`) ON UPDATE RESTRICT ON DELETE CASCADE,
+	FOREIGN KEY (`uid`) REFERENCES `user` (`uid`) ON UPDATE RESTRICT ON DELETE CASCADE
+) DEFAULT COLLATE utf8mb4_general_ci COMMENT='User post notifications';
+
 --
 -- TABLE process
 --
@@ -1429,23 +1446,6 @@ CREATE TABLE IF NOT EXISTS `user-contact` (
 	FOREIGN KEY (`uid`) REFERENCES `user` (`uid`) ON UPDATE RESTRICT ON DELETE CASCADE
 ) DEFAULT COLLATE utf8mb4_general_ci COMMENT='User specific public contact data';
 
---
--- TABLE user-item
---
-CREATE TABLE IF NOT EXISTS `user-item` (
-	`iid` int unsigned NOT NULL DEFAULT 0 COMMENT 'Item id',
-	`uid` mediumint unsigned NOT NULL DEFAULT 0 COMMENT 'User id',
-	`hidden` boolean NOT NULL DEFAULT '0' COMMENT 'Marker to hide an item from the user',
-	`ignored` boolean COMMENT 'Ignore this thread if set',
-	`pinned` boolean COMMENT 'The item is pinned on the profile page',
-	`notification-type` tinyint unsigned NOT NULL DEFAULT 0 COMMENT '',
-	 PRIMARY KEY(`uid`,`iid`),
-	 INDEX `uid_pinned` (`uid`,`pinned`),
-	 INDEX `iid_uid` (`iid`,`uid`),
-	FOREIGN KEY (`iid`) REFERENCES `item` (`id`) ON UPDATE RESTRICT ON DELETE CASCADE,
-	FOREIGN KEY (`uid`) REFERENCES `user` (`uid`) ON UPDATE RESTRICT ON DELETE CASCADE
-) DEFAULT COLLATE utf8mb4_general_ci COMMENT='User specific item data';
-
 --
 -- TABLE worker-ipc
 --
@@ -1848,13 +1848,13 @@ CREATE VIEW `network-item-view` AS SELECT
 	FROM `item`
 			INNER JOIN `thread` ON `thread`.`iid` = `item`.`parent`
 			STRAIGHT_JOIN `contact` ON `contact`.`id` = `thread`.`contact-id`
-			LEFT JOIN `user-item` ON `user-item`.`iid` = `item`.`id` AND `user-item`.`uid` = `thread`.`uid`
+			LEFT JOIN `post-user` ON `post-user`.`uri-id` = `item`.`uri-id` AND `post-user`.`uid` = `thread`.`uid`
 			LEFT JOIN `user-contact` AS `author` ON `author`.`uid` = `thread`.`uid` AND `author`.`cid` = `thread`.`author-id`
 			LEFT JOIN `user-contact` AS `owner` ON `owner`.`uid` = `thread`.`uid` AND `owner`.`cid` = `thread`.`owner-id`
 			LEFT JOIN `contact` AS `ownercontact` ON `ownercontact`.`id` = `thread`.`owner-id`
 			WHERE `thread`.`visible` AND NOT `thread`.`deleted` AND NOT `thread`.`moderated`
 			AND (NOT `contact`.`readonly` AND NOT `contact`.`blocked` AND NOT `contact`.`pending`)
-			AND (`user-item`.`hidden` IS NULL OR NOT `user-item`.`hidden`)
+			AND (`post-user`.`hidden` IS NULL OR NOT `post-user`.`hidden`)
 			AND (`author`.`blocked` IS NULL OR NOT `author`.`blocked`)
 			AND (`owner`.`blocked` IS NULL OR NOT `owner`.`blocked`);
 
@@ -1879,13 +1879,13 @@ CREATE VIEW `network-thread-view` AS SELECT
 	FROM `thread`
 			STRAIGHT_JOIN `contact` ON `contact`.`id` = `thread`.`contact-id`
 			STRAIGHT_JOIN `item` ON `item`.`id` = `thread`.`iid`
-			LEFT JOIN `user-item` ON `user-item`.`iid` = `item`.`id` AND `user-item`.`uid` = `thread`.`uid`
+			LEFT JOIN `post-user` ON `post-user`.`uri-id` = `item`.`uri-id` AND `post-user`.`uid` = `thread`.`uid`
 			LEFT JOIN `user-contact` AS `author` ON `author`.`uid` = `thread`.`uid` AND `author`.`cid` = `thread`.`author-id`
 			LEFT JOIN `user-contact` AS `owner` ON `owner`.`uid` = `thread`.`uid` AND `owner`.`cid` = `thread`.`owner-id`
 			LEFT JOIN `contact` AS `ownercontact` ON `ownercontact`.`id` = `thread`.`owner-id`
 			WHERE `thread`.`visible` AND NOT `thread`.`deleted` AND NOT `thread`.`moderated`
 			AND (NOT `contact`.`readonly` AND NOT `contact`.`blocked` AND NOT `contact`.`pending`)
-			AND (`user-item`.`hidden` IS NULL OR NOT `user-item`.`hidden`)
+			AND (`post-user`.`hidden` IS NULL OR NOT `post-user`.`hidden`)
 			AND (`author`.`blocked` IS NULL OR NOT `author`.`blocked`)
 			AND (`owner`.`blocked` IS NULL OR NOT `owner`.`blocked`);
 
diff --git a/doc/database.md b/doc/database.md
index e135b19ae..447607f8d 100644
--- a/doc/database.md
+++ b/doc/database.md
@@ -32,7 +32,6 @@ Database Tables
 | [notify-threads](help/database/db_notify-threads)    |                                                  |
 | [oembed](help/database/db_oembed)                    | cache for OEmbed queries                         |
 | [parsed_url](help/database/db_parsed_url)            | cache for "parse_url" queries                    |
-| [participation](help/database/db_participation)      | Storage for participation messages from Diaspora |
 | [pconfig](help/database/db_pconfig)                  | personal (per user) configuration storage        |
 | [photo](help/database/db_photo)                      | photo storage                                    |
 | [poll](help/database/db_poll)                        | data for polls                                   |
diff --git a/doc/database/db_particiation.md b/doc/database/db_particiation.md
deleted file mode 100644
index 27f063241..000000000
--- a/doc/database/db_particiation.md
+++ /dev/null
@@ -1,10 +0,0 @@
-Table participation
-===================
-
-| Field       | Description      | Type             | Null | Key | Default             | Extra |
-|-------------|------------------|------------------|------|-----|---------------------|-------|
-| iid         | item id          | int(10) unsigned | NO   | PRI |                     |       |
-| server      | Name of server   | varchar(60)      | NO   | PRI |                     |       |
-| cid         | contact id       | int(10) unsigned | NO   |     |                     |       |
-
-Return to [database documentation](help/database)
diff --git a/include/api.php b/include/api.php
index bcf14d6a8..4c90ab80d 100644
--- a/include/api.php
+++ b/include/api.php
@@ -43,7 +43,6 @@ use Friendica\Model\Notification;
 use Friendica\Model\Photo;
 use Friendica\Model\Post;
 use Friendica\Model\User;
-use Friendica\Model\UserItem;
 use Friendica\Model\Verb;
 use Friendica\Network\HTTPException;
 use Friendica\Network\HTTPException\BadRequestException;
@@ -2170,24 +2169,21 @@ function api_statuses_mentions($type)
 
 	$start = max(0, ($page - 1) * $count);
 
-	$query = "`gravity` IN (?, ?) AND `id` IN (SELECT `iid` FROM `user-item`		
-		WHERE (`hidden` IS NULL OR NOT `hidden`) AND
-			`uid` = ? AND `notification-type` & ? != 0
-			AND `iid` > ?";
+	$query = "`gravity` IN (?, ?) AND `uri-id` IN
+		(SELECT `uri-id` FROM `post-user-notification` WHERE `uid` = ? AND `notification-type` & ? != 0 ORDER BY `uri-id`)
+		AND (`uid` = 0 OR (`uid` = ? AND NOT `global`)) AND `id` > ?";
 
 	$condition = [GRAVITY_PARENT, GRAVITY_COMMENT, api_user(),
-		UserItem::NOTIF_EXPLICIT_TAGGED | UserItem::NOTIF_IMPLICIT_TAGGED |
-		UserItem::NOTIF_THREAD_COMMENT | UserItem::NOTIF_DIRECT_COMMENT |
-		UserItem::NOTIF_DIRECT_THREAD_COMMENT,
-		$since_id];
+		Post\UserNotification::NOTIF_EXPLICIT_TAGGED | Post\UserNotification::NOTIF_IMPLICIT_TAGGED |
+		Post\UserNotification::NOTIF_THREAD_COMMENT | Post\UserNotification::NOTIF_DIRECT_COMMENT |
+		Post\UserNotification::NOTIF_DIRECT_THREAD_COMMENT,
+		api_user(), $since_id];
 
 	if ($max_id > 0) {
-		$query .= " AND `iid` <= ?";
+		$query .= " AND `id` <= ?";
 		$condition[] = $max_id;
 	}
 
-	$query .= ")";
-
 	array_unshift($condition, $query);
 
 	$params = ['order' => ['id' => true], 'limit' => [$start, $count]];
diff --git a/include/enotify.php b/include/enotify.php
index eb5660327..8936cadbe 100644
--- a/include/enotify.php
+++ b/include/enotify.php
@@ -32,7 +32,6 @@ use Friendica\Model\Item;
 use Friendica\Model\Notification;
 use Friendica\Model\Post;
 use Friendica\Model\User;
-use Friendica\Model\UserItem;
 use Friendica\Protocol\Activity;
 
 /**
@@ -149,9 +148,8 @@ function notification($params)
 	}
 
 	if ($params['type'] == Notification\Type::COMMENT || $params['type'] == Notification\Type::TAG_SELF) {
-		$thread = Post::selectFirstThreadForUser($params['uid'], ['ignored'], ['iid' => $parent_id, 'deleted' => false]);
-		if (DBA::isResult($thread) && $thread['ignored']) {
-			Logger::log('Thread ' . $parent_id . ' will be ignored', Logger::DEBUG);
+		if (Post\ThreadUser::getIgnored($parent_uri_id, $params['uid'])) {
+			Logger::info('Thread is ignored', ['parent' => $parent_id, 'parent-uri-id' => $parent_uri_id]);
 			return false;
 		}
 
@@ -593,32 +591,39 @@ function notification($params)
 /**
  * Checks for users who should be notified
  *
- * @param int $itemid ID of the item for which the check should be done
+ * @param int $uri_id URI ID of the item for which the check should be done
+ * @param int $uid    User ID of the item
  * @throws \Friendica\Network\HTTPException\InternalServerErrorException
  */
-function check_user_notification($itemid) {
-	// fetch all users with notifications
-	$useritems = DBA::select('user-item', ['uid', 'notification-type'], ['iid' => $itemid]);
-	while ($useritem = DBA::fetch($useritems)) {
-		check_item_notification($itemid, $useritem['uid'], $useritem['notification-type']);
+function check_user_notification(int $uri_id, int $uid) {
+	$condition = ['uri-id' => $uri_id];
+
+	// fetch all users with notifications on public posts
+	if ($uid != 0) {
+		$condition['uid'] = $uid;
 	}
-	DBA::close($useritems);
+
+	$usernotifications = DBA::select('post-user-notification', ['uri-id', 'uid', 'notification-type'], $condition);
+	while ($usernotification = DBA::fetch($usernotifications)) {
+		check_item_notification($usernotification['uri-id'], $usernotification['uid'], $usernotification['notification-type']);
+	}
+	DBA::close($usernotifications);
 }
 
 /**
  * Checks for item related notifications and sends them
  *
- * @param int    $itemid            ID of the item for which the check should be done
+ * @param int    $uri_id            URI ID of the item for which the check should be done
  * @param int    $uid               User ID
  * @param int    $notification_type Notification bits
  * @return bool
  * @throws \Friendica\Network\HTTPException\InternalServerErrorException
  */
-function check_item_notification($itemid, $uid, $notification_type) {
+function check_item_notification(int $uri_id, int $uid, int $notification_type) {
 	$fields = ['id', 'uri-id', 'mention', 'parent', 'parent-uri-id', 'thr-parent-id',
 		'title', 'body', 'author-link', 'author-name', 'author-avatar', 'author-id',
 		'gravity', 'guid', 'parent-uri', 'uri', 'contact-id', 'network'];
-	$condition = ['id' => $itemid, 'deleted' => false];
+	$condition = ['uri-id' => $uri_id, 'uid' => $uid, 'deleted' => false];
 	$item = Post::selectFirstForUser($uid, $fields, $condition);
 	if (!DBA::isResult($item)) {
 		return false;
@@ -638,19 +643,19 @@ function check_item_notification($itemid, $uid, $notification_type) {
 	$params['link'] = DI::baseUrl() . '/display/' . urlencode($item['guid']);
 
 	// Set the activity flags
-	$params['activity']['explicit_tagged'] = ($notification_type & UserItem::NOTIF_EXPLICIT_TAGGED);
-	$params['activity']['implicit_tagged'] = ($notification_type & UserItem::NOTIF_IMPLICIT_TAGGED);
-	$params['activity']['origin_comment'] = ($notification_type & UserItem::NOTIF_DIRECT_COMMENT);
-	$params['activity']['origin_thread'] = ($notification_type & UserItem::NOTIF_THREAD_COMMENT);
-	$params['activity']['thread_comment'] = ($notification_type & UserItem::NOTIF_COMMENT_PARTICIPATION);
-	$params['activity']['thread_activity'] = ($notification_type & UserItem::NOTIF_ACTIVITY_PARTICIPATION);
+	$params['activity']['explicit_tagged'] = ($notification_type & Post\UserNotification::NOTIF_EXPLICIT_TAGGED);
+	$params['activity']['implicit_tagged'] = ($notification_type & Post\UserNotification::NOTIF_IMPLICIT_TAGGED);
+	$params['activity']['origin_comment'] = ($notification_type & Post\UserNotification::NOTIF_DIRECT_COMMENT);
+	$params['activity']['origin_thread'] = ($notification_type & Post\UserNotification::NOTIF_THREAD_COMMENT);
+	$params['activity']['thread_comment'] = ($notification_type & Post\UserNotification::NOTIF_COMMENT_PARTICIPATION);
+	$params['activity']['thread_activity'] = ($notification_type & Post\UserNotification::NOTIF_ACTIVITY_PARTICIPATION);
 
 	// Tagging a user in a direct post (first comment level) means a direct comment
-	if ($params['activity']['explicit_tagged'] && ($notification_type & UserItem::NOTIF_DIRECT_THREAD_COMMENT)) {
+	if ($params['activity']['explicit_tagged'] && ($notification_type & Post\UserNotification::NOTIF_DIRECT_THREAD_COMMENT)) {
 		$params['activity']['origin_comment'] = true;
 	}
 
-	if ($notification_type & UserItem::NOTIF_SHARED) {
+	if ($notification_type & Post\UserNotification::NOTIF_SHARED) {
 		$params['type'] = Notification\Type::SHARE;
 		$params['verb'] = Activity::POST;
 
@@ -667,22 +672,22 @@ function check_item_notification($itemid, $uid, $notification_type) {
 				$params['item'] = $parent_item;
 			}
 		}
-	} elseif ($notification_type & UserItem::NOTIF_EXPLICIT_TAGGED) {
+	} elseif ($notification_type & Post\UserNotification::NOTIF_EXPLICIT_TAGGED) {
 		$params['type'] = Notification\Type::TAG_SELF;
 		$params['verb'] = Activity::TAG;
-	} elseif ($notification_type & UserItem::NOTIF_IMPLICIT_TAGGED) {
+	} elseif ($notification_type & Post\UserNotification::NOTIF_IMPLICIT_TAGGED) {
 		$params['type'] = Notification\Type::COMMENT;
 		$params['verb'] = Activity::POST;
-	} elseif ($notification_type & UserItem::NOTIF_THREAD_COMMENT) {
+	} elseif ($notification_type & Post\UserNotification::NOTIF_THREAD_COMMENT) {
 		$params['type'] = Notification\Type::COMMENT;
 		$params['verb'] = Activity::POST;
-	} elseif ($notification_type & UserItem::NOTIF_DIRECT_COMMENT) {
+	} elseif ($notification_type & Post\UserNotification::NOTIF_DIRECT_COMMENT) {
 		$params['type'] = Notification\Type::COMMENT;
 		$params['verb'] = Activity::POST;
-	} elseif ($notification_type & UserItem::NOTIF_COMMENT_PARTICIPATION) {
+	} elseif ($notification_type & Post\UserNotification::NOTIF_COMMENT_PARTICIPATION) {
 		$params['type'] = Notification\Type::COMMENT;
 		$params['verb'] = Activity::POST;
-	} elseif ($notification_type & UserItem::NOTIF_ACTIVITY_PARTICIPATION) {
+	} elseif ($notification_type & Post\UserNotification::NOTIF_ACTIVITY_PARTICIPATION) {
 		$params['type'] = Notification\Type::COMMENT;
 		$params['verb'] = Activity::POST;
 	} else {
diff --git a/src/Database/DBStructure.php b/src/Database/DBStructure.php
index 8a3d6cc80..b9e53be04 100644
--- a/src/Database/DBStructure.php
+++ b/src/Database/DBStructure.php
@@ -79,7 +79,8 @@ class DBStructure
 		}
 
 		$old_tables = ['fserver', 'gcign', 'gcontact', 'gcontact-relation', 'gfollower' ,'glink', 'item-delivery-data',
-			'item-activity', 'item-content', 'item_id', 'poll', 'poll_result', 'queue', 'retriever_rule', 'sign', 'spam', 'term'];
+			'item-activity', 'item-content', 'item_id', 'participation', 'poll', 'poll_result', 'queue', 'retriever_rule',
+			'sign', 'spam', 'term', 'user-item'];
 
 		$tables = DBA::selectToArray(['INFORMATION_SCHEMA' => 'TABLES'], ['TABLE_NAME'],
 			['TABLE_SCHEMA' => DBA::databaseName(), 'TABLE_TYPE' => 'BASE TABLE']);
diff --git a/src/Database/PostUpdate.php b/src/Database/PostUpdate.php
index 51ce0d2b5..3a1333780 100644
--- a/src/Database/PostUpdate.php
+++ b/src/Database/PostUpdate.php
@@ -31,7 +31,6 @@ use Friendica\Model\Photo;
 use Friendica\Model\Post;
 use Friendica\Model\Post\Category;
 use Friendica\Model\Tag;
-use Friendica\Model\UserItem;
 use Friendica\Model\Verb;
 use Friendica\Util\Strings;
 
@@ -168,7 +167,7 @@ class PostUpdate
 	}
 
 	/**
-	 * update user-item data with notifications
+	 * update user notification data
 	 *
 	 * @return bool "true" when the job is done
 	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
@@ -188,7 +187,7 @@ class PostUpdate
 		$rows = 0;
 		$condition = ["`id` > ?", $id];
 		$params = ['order' => ['id'], 'limit' => 10000];
-		$items = DBA::select('item', ['id'], $condition, $params);
+		$items = DBA::select('item', ['id', 'uri-id', 'uid'], $condition, $params);
 
 		if (DBA::errorNo() != 0) {
 			Logger::error('Database error', ['no' => DBA::errorNo(), 'message' => DBA::errorMessage()]);
@@ -198,7 +197,7 @@ class PostUpdate
 		while ($item = DBA::fetch($items)) {
 			$id = $item['id'];
 
-			UserItem::setNotification($item['id']);
+			Post\UserNotification::setNotification($item['uri-id'], $item['uid']);
 
 			++$rows;
 		}
diff --git a/src/Factory/Api/Mastodon/Status.php b/src/Factory/Api/Mastodon/Status.php
index cd611e8ee..6a3212c26 100644
--- a/src/Factory/Api/Mastodon/Status.php
+++ b/src/Factory/Api/Mastodon/Status.php
@@ -77,9 +77,9 @@ class Status extends BaseFactory
 		$userAttributes = new \Friendica\Object\Api\Mastodon\Status\UserAttributes(
 			Post::exists(['thr-parent-id' => $uriId, 'uid' => $uid, 'origin' => true, 'gravity' => GRAVITY_ACTIVITY, 'vid' => Verb::getID(Activity::LIKE)]),
 			Post::exists(['thr-parent-id' => $uriId, 'uid' => $uid, 'origin' => true, 'gravity' => GRAVITY_ACTIVITY, 'vid' => Verb::getID(Activity::ANNOUNCE)]),
-			DBA::exists('thread', ['iid' => $item['id'], 'uid' => $item['uid'], 'ignored' => true]),
+			Post\ThreadUser::getIgnored($uriId, $item['uid']),
 			(bool)$item['starred'],
-			DBA::exists('user-item', ['iid' => $item['id'], 'uid' => $item['uid'], 'pinned' => true])
+			Post\ThreadUser::getPinned($uriId, $item['uid'])
 		);
 
 		$sensitive = DBA::exists('tag-view', ['uri-id' => $uriId, 'name' => 'nsfw']);
diff --git a/src/Model/Item.php b/src/Model/Item.php
index 6d882463f..5041b7ef5 100644
--- a/src/Model/Item.php
+++ b/src/Model/Item.php
@@ -31,7 +31,6 @@ use Friendica\Core\Session;
 use Friendica\Core\System;
 use Friendica\Model\Tag;
 use Friendica\Core\Worker;
-use Friendica\Database\Database;
 use Friendica\Database\DBA;
 use Friendica\Database\DBStructure;
 use Friendica\DI;
@@ -99,14 +98,6 @@ class Item
 			'author-id', 'author-link', 'owner-link', 'contact-uid',
 			'signed_text', 'network'];
 
-	// Field list for "post-content" table that is mixed with the item table
-	const MIXED_CONTENT_FIELDLIST = ['title', 'content-warning', 'body', 'location',
-			'coord', 'app', 'rendered-hash', 'rendered-html', 'verb',
-			'object-type', 'object', 'target-type', 'target', 'plink'];
-
-	// Field list for "post-content" table that is not present in the "item" table
-	const CONTENT_FIELDLIST = ['language', 'raw-body'];
-
 	// All fields in the item table
 	const ITEM_FIELDLIST = ['id', 'uid', 'parent', 'uri', 'parent-uri', 'thr-parent',
 			'guid', 'uri-id', 'parent-uri-id', 'thr-parent-id', 'vid',
@@ -121,6 +112,22 @@ class Item
 			'author-id', 'author-link', 'author-name', 'author-avatar', 'author-network',
 			'owner-id', 'owner-link', 'owner-name', 'owner-avatar', 'causer-id'];
 
+	// Item fiels that still are in use
+	const USED_FIELDLIST = ['id', 'parent', 'guid', 'uri', 'uri-id', 'parent-uri', 'parent-uri-id',
+		'thr-parent', 'thr-parent-id', 'created', 'edited', 'commented', 'received', 'changed',
+		'gravity', 'network', 'owner-id', 'author-id', 'causer-id', 'vid', 'extid', 'post-type',
+		'global', 'private', 'visible', 'moderated', 'deleted', 'uid', 'contact-id',
+		'wall', 'origin', 'pubmail', 'starred', 'unseen', 'mention', 'forum_mode', 'psid',
+		'event-id', 'type', 'bookmark'];
+
+	// Legacy item fields that aren't stored any more in the item table
+	const LEGACY_FIELDLIST = ['uri-hash', 'iaid', 'icid', 'attach',
+		'allow_cid', 'allow_gid', 'deny_cid', 'deny_gid', 'postopts', 
+		'resource-id', 'inform', 'file', 'location', 'coord', 'tag', 'plink', 
+		'title', 'content-warning', 'body', 'app', 'verb', 'object-type', 'object', 
+		'target-type', 'target', 'author-name', 'author-link', 'author-avatar', 
+		'owner-name', 'owner-link', 'owner-avatar', 'rendered-hash', 'rendered-html'];
+
 	// List of all verbs that don't need additional content data.
 	// Never reorder or remove entries from this list. Just add new ones at the end, if needed.
 	const ACTIVITIES = [
@@ -133,49 +140,6 @@ class Item
 	const PRIVATE = 1;
 	const UNLISTED = 2;
 
-	const TABLES = ['item', 'user-item', 'post-content', 'post-delivery-data', 'diaspora-interaction'];
-
-	private static function getItemFields()
-	{
-		$definition = DBStructure::definition('', false);
-
-		$postfields = [];
-		foreach (self::TABLES as $table) {
-			$postfields[$table] = array_keys($definition[$table]['fields']);
-		}
-
-		return $postfields;
-	}
-
-	/**
-	 * Set the pinned state of an item
-	 *
-	 * @param integer $iid    Item ID
-	 * @param integer $uid    User ID
-	 * @param boolean $pinned Pinned state
-	 */
-	public static function setPinned(int $iid, int $uid, bool $pinned)
-	{
-		DBA::update('user-item', ['pinned' => $pinned], ['iid' => $iid, 'uid' => $uid], true);
-	}
-
-	/**
-	 * Get the pinned state
-	 *
-	 * @param integer $iid Item ID
-	 * @param integer $uid User ID
-	 *
-	 * @return boolean pinned state
-	 */
-	public static function getPinned(int $iid, int $uid)
-	{
-		$useritem = DBA::selectFirst('user-item', ['pinned'], ['iid' => $iid, 'uid' => $uid]);
-		if (!DBA::isResult($useritem)) {
-			return false;
-		}
-		return (bool)$useritem['pinned'];
-	}
-
 	/**
 	 * Update existing item entries
 	 *
@@ -285,12 +249,9 @@ class Item
 				Post\User::update($item['uri-id'], $uid, ['hidden' => true], true);
 			}
 
-			// "Deleting" global items just means hiding them
-			if ($item['uid'] == 0) {
-				DBA::update('user-item', ['hidden' => true], ['iid' => $item['id'], 'uid' => $uid], true);
-			} elseif ($item['uid'] == $uid) {
+			if ($item['uid'] == $uid) {
 				self::markForDeletionById($item['id'], PRIORITY_HIGH);
-			} else {
+			} elseif ($item['uid'] != 0) {
 				Logger::log('Wrong ownership. Not deleting item ' . $item['id']);
 			}
 		}
@@ -393,12 +354,6 @@ class Item
 			}
 		} elseif ($item['uid'] != 0) {
 			Post\User::update($item['uri-id'], $item['uid'], ['hidden' => true]);
-
-			// When we delete just our local user copy of an item, we have to set a marker to hide it
-			$global_item = Post::selectFirst(['id'], ['uri-id' => $item['uri-id'], 'uid' => 0, 'deleted' => false]);
-			if (DBA::isResult($global_item)) {
-				DBA::update('user-item', ['hidden' => true], ['iid' => $global_item['id'], 'uid' => $item['uid']], true);
-			}
 		}
 
 		Logger::info('Item has been marked for deletion.', ['id' => $item_id]);
@@ -755,8 +710,6 @@ class Item
 
 	public static function insert($item, $notify = false, $dontcache = false)
 	{
-		$structure = self::getItemFields();
-
 		$orig_item = $item;
 
 		$priority = PRIORITY_HIGH;
@@ -952,26 +905,11 @@ class Item
 
 			// Update the contact relations
 			Contact\Relation::store($toplevel_parent['author-id'], $item['author-id'], $item['created']);
-
-			unset($item['parent_origin']);
 		} else {
 			$parent_id = 0;
 			$parent_origin = $item['origin'];
 		}
 
-		// We don't store the causer link, only the id
-		unset($item['causer-link']);
-
-		// We don't store these fields anymore in the item table
-		unset($item['author-link']);
-		unset($item['author-name']);
-		unset($item['author-avatar']);
-		unset($item['author-network']);
-
-		unset($item['owner-link']);
-		unset($item['owner-name']);
-		unset($item['owner-avatar']);
-
 		$item['parent-uri-id'] = ItemURI::getIdByURI($item['parent-uri']);
 		$item['thr-parent-id'] = ItemURI::getIdByURI($item['thr-parent']);
 
@@ -994,14 +932,10 @@ class Item
 			$item['edit'] = false;
 			$item['parent'] = $parent_id;
 			Hook::callAll('post_local', $item);
-			unset($item['edit']);
 		} else {
 			Hook::callAll('post_remote', $item);
 		}
 
-		// Set after the insert because top-level posts are self-referencing
-		unset($item['parent']);
-
 		if (!empty($item['cancel'])) {
 			Logger::log('post cancelled by addon.');
 			return 0;
@@ -1020,15 +954,6 @@ class Item
 			$item['deny_gid']
 		);
 
-		unset($item['allow_cid']);
-		unset($item['allow_gid']);
-		unset($item['deny_cid']);
-		unset($item['deny_gid']);
-
-		// This array field is used to trigger some automatic reactions
-		// It is mainly used in the "post_local" hook.
-		unset($item['api_source']);
-
 		if ($item['verb'] == Activity::ANNOUNCE) {
 			self::setOwnerforResharedItem($item);
 		}
@@ -1040,10 +965,6 @@ class Item
 		// Check for hashtags in the body and repair or add hashtag links
 		$item['body'] = self::setHashtags($item['body']);
 
-		if (!empty($item['attach'])) {
-			Post\Media::insertFromAttachment($item['uri-id'], $item['attach']);
-		}
-
 		// Fill the cache field
 		self::putInCache($item);
 
@@ -1053,40 +974,27 @@ class Item
 			$notify_type = Delivery::POST;
 		}
 
+		// Filling item related side tables
+		if (!empty($item['attach'])) {
+			Post\Media::insertFromAttachment($item['uri-id'], $item['attach']);
+		}
+
 		if (!in_array($item['verb'], self::ACTIVITIES)) {
 			Post\Content::insert($item['uri-id'], $item);
 		}
 
-		$body = $item['body'];
-		$verb = $item['verb'];
-
-		// We just remove everything that is content
-		foreach (array_merge(self::CONTENT_FIELDLIST, self::MIXED_CONTENT_FIELDLIST) as $field) {
-			unset($item[$field]);
-		}
-
-		unset($item['activity']);
-
-		// Filling item related side tables
-
 		// Diaspora signature
 		if (!empty($item['diaspora_signed_text'])) {
 			DBA::replace('diaspora-interaction', ['uri-id' => $item['uri-id'], 'interaction' => $item['diaspora_signed_text']]);
 		}
 
-		unset($item['diaspora_signed_text']);
-
 		// Attached file links
 		if (!empty($item['file'])) {
 			Post\Category::storeTextByURIId($item['uri-id'], $item['uid'], $item['file']);
 		}
 
-		unset($item['file']);
-
 		// Delivery relevant data
 		$delivery_data = Post\DeliveryData::extractFields($item);
-		unset($item['postopts']);
-		unset($item['inform']);
 
 		if (!empty($item['origin']) || !empty($item['wall']) || !empty($delivery_data['postopts']) || !empty($delivery_data['inform'])) {
 			Post\DeliveryData::insert($item['uri-id'], $delivery_data);
@@ -1094,33 +1002,38 @@ class Item
 
 		// Store tags from the body if this hadn't been handled previously in the protocol classes
 		if (!Tag::existsForPost($item['uri-id'])) {
-			Tag::storeFromBody($item['uri-id'], $body);
+			Tag::storeFromBody($item['uri-id'], $item['body']);
 		}
 
 		$id = Post\User::insert($item['uri-id'], $item['uid'], $item);
-		if ($id) {
-			// Remove all fields that aren't part of the item table
-			foreach ($item as $field => $value) {
-				if (!in_array($field, $structure['item'])) {
-					unset($item[$field]);
-				}
-			}
-
-			$condition = ['uri-id' => $item['uri-id'], 'uid' => $item['uid'], 'network' => $item['network']];
-			if (Post::exists($condition)) {
-				Logger::notice('Item is already inserted - aborting', $condition);
-				return 0;
-			}
-
-			$result = DBA::insert('item', $item);
-
-			// When the item was successfully stored we fetch the ID of the item.
-			$current_post = DBA::lastInsertId();
-		} else {
+		if (!$id) {
 			Logger::notice('Post-User is already inserted - aborting', ['uid' => $item['uid'], 'uri-id' => $item['uri-id']]);
 			return 0;
 		}
 
+		if ($item['gravity'] == GRAVITY_PARENT) {
+			Post\ThreadUser::insert($item['uri-id'], $item['uid'], $item);
+		}
+
+		$condition = ['uri-id' => $item['uri-id'], 'uid' => $item['uid'], 'network' => $item['network']];
+		if (Post::exists($condition)) {
+			Logger::notice('Item is already inserted - aborting', $condition);
+			return 0;
+		}
+
+		// Remove all fields that aren't part of the item table
+		$table_fields = DBStructure::getFieldsForTable('item', $item);
+
+		// We remove all legacy fields that now are stored in other tables
+		foreach (self::LEGACY_FIELDLIST as $field) {
+			unset($table_fields[$field]);
+		}
+
+		$result = DBA::insert('item', $table_fields);
+
+		// When the item was successfully stored we fetch the ID of the item.
+		$current_post = DBA::lastInsertId();
+
 		if (empty($current_post) || !DBA::isResult($result)) {
 			// On failure store the data into a spool file so that the "SpoolPost" worker can try again later.
 			Logger::warning('Could not store item. it will be spooled', ['result' => $result, 'id' => $current_post]);
@@ -1146,7 +1059,7 @@ class Item
 			$update_commented = in_array($item['gravity'], [GRAVITY_PARENT, GRAVITY_COMMENT]);
 		} else {
 			// Update when it isn't a follow or tag verb
-			$update_commented = !in_array($verb, [Activity::FOLLOW, Activity::TAG]);
+			$update_commented = !in_array($item['verb'], [Activity::FOLLOW, Activity::TAG]);
 		}
 
 		if ($update_commented) {
@@ -1191,9 +1104,10 @@ class Item
 
 		self::updateContact($item);
 
-		UserItem::setNotification($current_post);
+		Post\UserNotification::setNotification($item['uri-id'], $item['uid']);
 
-		check_user_notification($current_post);
+		check_user_notification($item['uri-id'], $item['uid']);
+		//check_user_notification($current_post);
 
 		// Distribute items to users who subscribed to their tags
 		self::distributeByTags($item);
diff --git a/src/Model/Post.php b/src/Model/Post.php
index 59e2f419c..73742b3b2 100644
--- a/src/Model/Post.php
+++ b/src/Model/Post.php
@@ -192,7 +192,7 @@ class Post
 			$selected = array_merge(['author-addr', 'author-nick', 'owner-addr', 'owner-nick', 'causer-addr', 'causer-nick',
 				'causer-network', 'photo', 'name-date', 'uri-date', 'avatar-date', 'thumb', 'dfrn-id',
 				'parent-guid', 'parent-network', 'parent-author-id', 'parent-author-link', 'parent-author-name',
-				'parent-author-network', 'signed_text'], Item::DISPLAY_FIELDLIST, Item::ITEM_FIELDLIST, Item::CONTENT_FIELDLIST);
+				'parent-author-network', 'signed_text', 'language', 'raw-body'], Item::DISPLAY_FIELDLIST, Item::ITEM_FIELDLIST);
 			
 			if ($view == 'post-thread-view') {
 				$selected = array_merge($selected, ['ignored', 'iid']);
@@ -258,7 +258,7 @@ class Post
 			AND (NOT `causer-blocked` OR `causer-id` = ?) AND NOT `contact-blocked`
 			AND ((NOT `contact-readonly` AND NOT `contact-pending` AND (`contact-rel` IN (?, ?)))
 				OR `self` OR `gravity` != ? OR `contact-uid` = ?)
-			AND NOT EXISTS (SELECT `iid` FROM `user-item` WHERE `hidden` AND `iid` = `id` AND `uid` = ?)
+			AND NOT EXISTS (SELECT `uri-id` FROM `post-user` WHERE `hidden` AND `uri-id` = `" . $view . "`.`uri-id` AND `uid` = ?)
 			AND NOT EXISTS (SELECT `cid` FROM `user-contact` WHERE `uid` = ? AND `cid` = `author-id` AND `blocked`)
 			AND NOT EXISTS (SELECT `cid` FROM `user-contact` WHERE `uid` = ? AND `cid` = `owner-id` AND `blocked`)
 			AND NOT EXISTS (SELECT `cid` FROM `user-contact` WHERE `uid` = ? AND `cid` = `author-id` AND `ignored` AND `gravity` = ?)
@@ -272,7 +272,7 @@ class Post
 			unset($selected['pinned']);
 			$selected = array_flip($selected);	
 
-			$select_string = "(SELECT `pinned` FROM `user-item` WHERE `iid` = `" . $view . "`.`id` AND uid=`" . $view . "`.`uid`) AS `pinned`, ";
+			$select_string = "(SELECT `pinned` FROM `post-thread-user` WHERE `uri-id` = `" . $view . "`.`uri-id` AND uid=`" . $view . "`.`uid`) AS `pinned`, ";
 		}
 
 		$select_string .= implode(', ', array_map([DBA::class, 'quoteIdentifier'], $selected));
@@ -344,32 +344,6 @@ class Post
 		}
 	}
 
-	/**
-	 * Retrieve a single record from the starting post in the item table and returns it in an associative array
-	 *
-	 * @param integer $uid User ID
-	 * @param array   $selected
-	 * @param array   $condition
-	 * @param array   $params
-	 * @return bool|array
-	 * @throws \Exception
-	 * @see   DBA::select
-	 */
-	public static function selectFirstThreadForUser($uid, array $selected = [], array $condition = [], $params = [])
-	{
-		$params['limit'] = 1;
-
-		$result = self::selectThreadForUser($uid, $selected, $condition, $params);
-
-		if (is_bool($result)) {
-			return $result;
-		} else {
-			$row = self::fetch($result);
-			DBA::close($result);
-			return $row;
-		}
-	}
-
 	/**
 	 * Select pinned rows from the item table for a given user
 	 *
@@ -383,24 +357,24 @@ class Post
 	 */
 	public static function selectPinned(int $uid, array $selected = [], array $condition = [], $params = [])
 	{
-		$useritems = DBA::select('user-item', ['iid'], ['uid' => $uid, 'pinned' => true]);
-		if (!DBA::isResult($useritems)) {
-			return $useritems;
+		$postthreaduser = DBA::select('post-thread-user', ['uri-id'], ['uid' => $uid, 'pinned' => true]);
+		if (!DBA::isResult($postthreaduser)) {
+			return $postthreaduser;
 		}
-
+	
 		$pinned = [];
-		while ($useritem = DBA::fetch($useritems)) {
-			$pinned[] = $useritem['iid'];
+		while ($useritem = DBA::fetch($postthreaduser)) {
+			$pinned[] = $useritem['uri-id'];
 		}
-		DBA::close($useritems);
+		DBA::close($postthreaduser);
 
 		if (empty($pinned)) {
 			return [];
 		}
 
-		$condition = DBA::mergeConditions(['iid' => $pinned], $condition);
+		$condition = DBA::mergeConditions(['uri-id' => $pinned, 'uid' => $uid, 'gravity' => GRAVITY_PARENT], $condition);
 
-		return self::selectThreadForUser($uid, $selected, $condition, $params);
+		return self::selectForUser($uid, $selected, $condition, $params);
 	}
 
 	/**
@@ -431,6 +405,8 @@ class Post
 		unset($fields['parent-uri']);
 		unset($fields['parent-uri-id']);
 
+		$thread_condition = DBA::mergeConditions($condition, ['gravity' => GRAVITY_PARENT]);
+
 		// To ensure the data integrity we do it in an transaction
 		DBA::transaction();
 
@@ -472,34 +448,44 @@ class Post
 			$affected = max($affected, DBA::affectedRows());
 		}
 
-		$update_fields = DBStructure::getFieldsForTable('thread', $fields);
+		$update_fields = DBStructure::getFieldsForTable('post-thread-user', $fields);
 		if (!empty($update_fields)) {
-			$rows = DBA::selectToArray('post-view', ['id'], $condition);
-			$ids = array_column($rows, 'id');
-			if (!DBA::update('thread', $update_fields, ['iid' => $ids])) {
+			$rows = DBA::selectToArray('post-view', ['post-user-id'], $thread_condition);
+			$thread_puids = array_column($rows, 'post-user-id');
+
+			$post_thread_condition = DBA::collapseCondition(['id' => $thread_puids]);
+
+			$post_thread_condition[0] = "EXISTS(SELECT `id` FROM `post-user` WHERE " .
+				$post_thread_condition[0] . " AND `uri-id` = `post-thread-user`.`uri-id` AND `uid` = `post-thread-user`.`uid`)";
+				if (!DBA::update('post-thread-user', $update_fields, $post_thread_condition)) {
 				DBA::rollback();
-				Logger::notice('Updating thread failed', ['fields' => $update_fields, 'condition' => $condition]);
+				Logger::notice('Updating post-thread-user failed', ['fields' => $update_fields, 'condition' => $condition]);
 				return false;
 			}
 			$affected = max($affected, DBA::affectedRows());
 		}
 
-		$item_fields = ['guid', 'type', 'wall', 'gravity', 'extid', 'created', 'edited', 'commented', 'received', 'changed',
-			'resource-id', 'post-type', 'private', 'pubmail', 'moderated', 'visible', 'starred', 'bookmark',
-			'unseen', 'deleted', 'origin', 'forum_mode', 'mention', 'global', 'network', 'vid', 'psid',
-			'contact-id', 'author-id', 'owner-id', 'causer-id', 'event-id'];
+		$update_fields = DBStructure::getFieldsForTable('thread', $fields);
+		if (!empty($update_fields)) {
+			$rows = DBA::selectToArray('post-view', ['id'], $thread_condition);
+			$ids = array_column($rows, 'id');
+			if (!DBA::update('thread', $update_fields, ['iid' => $ids])) {
+				DBA::rollback();
+				Logger::notice('Updating thread failed', ['fields' => $update_fields, 'condition' => $thread_condition]);
+				return false;
+			}
+			$affected = max($affected, DBA::affectedRows());
+		}
 
 		$update_fields = [];
-		foreach ($item_fields as $field) {
+		foreach (Item::USED_FIELDLIST as $field) {
 			if (array_key_exists($field, $fields)) {
 				$update_fields[$field] = $fields[$field];
 			}
 		}
 		if (!empty($update_fields)) {
-			if (empty($ids)) {
-				$rows = DBA::selectToArray('post-view', ['id'], $condition, []);
-				$ids = array_column($rows, 'id');
-			}
+			$rows = DBA::selectToArray('post-view', ['id'], $condition, []);
+			$ids = array_column($rows, 'id');
 			if (!DBA::update('item', $update_fields, ['id' => $ids])) {
 				DBA::rollback();
 				Logger::notice('Updating item failed', ['fields' => $update_fields, 'condition' => $condition]);
diff --git a/src/Model/Post/ThreadUser.php b/src/Model/Post/ThreadUser.php
new file mode 100644
index 000000000..f0f2f17a0
--- /dev/null
+++ b/src/Model/Post/ThreadUser.php
@@ -0,0 +1,153 @@
+<?php
+/**
+ * @copyright Copyright (C) 2020, Friendica
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Friendica\Model\Post;
+
+use \BadMethodCallException;
+use Friendica\Database\Database;
+use Friendica\Database\DBA;
+use Friendica\Database\DBStructure;
+
+class ThreadUser
+{
+	/**
+	 * Insert a new URI user entry
+	 *
+	 * @param integer $uri_id
+	 * @param integer $uid
+	 * @param array   $fields
+	 * @return bool   success
+	 * @throws \Exception
+	 */
+	public static function insert(int $uri_id, int $uid, array $data = [])
+	{
+		if (empty($uri_id)) {
+			throw new BadMethodCallException('Empty URI_id');
+		}
+
+		$fields = DBStructure::getFieldsForTable('post-thread-user', $data);
+
+		// Additionally assign the key fields
+		$fields['uri-id'] = $uri_id;
+		$fields['uid'] = $uid;
+
+		return DBA::insert('post-thread-user', $fields, Database::INSERT_IGNORE);
+	}
+
+	/**
+	 * Update a URI user entry
+	 *
+	 * @param integer $uri_id
+	 * @param integer $uid
+	 * @param array   $data
+	 * @param bool    $insert_if_missing
+	 * @return bool
+	 * @throws \Exception
+	 */
+	public static function update(int $uri_id, int $uid, array $data = [], bool $insert_if_missing = false)
+	{
+		if (empty($uri_id)) {
+			throw new BadMethodCallException('Empty URI_id');
+		}
+
+		$fields = DBStructure::getFieldsForTable('post-thread-user', $data);
+
+		// Remove the key fields
+		unset($fields['uri-id']);
+		unset($fields['uid']);
+
+		if (empty($fields)) {
+			return true;
+		}
+
+		return DBA::update('post-thread-user', $fields, ['uri-id' => $uri_id, 'uid' => $uid], $insert_if_missing ? true : []);
+	}
+
+	/**
+	 * Delete a row from the post-thread-user table
+	 *
+	 * @param array        $conditions Field condition(s)
+	 * @param array        $options
+	 *                           - cascade: If true we delete records in other tables that depend on the one we're deleting through
+	 *                           relations (default: true)
+	 *
+	 * @return boolean was the delete successful?
+	 * @throws \Exception
+	 */
+	public static function delete(array $conditions, array $options = [])
+	{
+		return DBA::delete('post-thread-user', $conditions, $options);
+	}
+
+	/**
+	 * @param int $uri_id 
+	 * @param int $uid 
+	 * @return bool 
+	 * @throws Exception 
+	 */
+	public static function getIgnored(int $uri_id, int $uid)
+	{
+		$threaduser = DBA::selectFirst('post-thread-user', ['ignored'], ['uri-id' => $uri_id, 'uid' => $uid]);
+		if (empty($threaduser)) {
+			return false;
+		}
+		return (bool)$threaduser['ignored'];
+	}
+
+	/**
+	 * @param int $uri_id 
+	 * @param int $uid 
+	 * @param int $ignored 
+	 * @return void 
+	 * @throws Exception 
+	 */
+	public static function setIgnored(int $uri_id, int $uid, int $ignored)
+	{
+		DBA::update('post-thread-user', ['ignored' => $ignored], ['uri-id' => $uri_id, 'uid' => $uid], true);
+	}
+
+	/**
+	 * @param int $uri_id 
+	 * @param int $uid 
+	 * @return bool 
+	 * @throws Exception 
+	 */
+	public static function getPinned(int $uri_id, int $uid)
+	{
+		$threaduser = DBA::selectFirst('post-thread-user', ['pinned'], ['uri-id' => $uri_id, 'uid' => $uid]);
+		if (empty($threaduser)) {
+			return false;
+		}
+		return (bool)$threaduser['pinned'];
+	}
+
+	/**
+	 * @param int $uri_id 
+	 * @param int $uid 
+	 * @param int $pinned 
+	 * @return void 
+	 * @throws Exception 
+	 */
+	public static function setPinned(int $uri_id, int $uid, int $pinned)
+	{
+		DBA::update('post-thread-user', ['pinned' => $pinned], ['uri-id' => $uri_id, 'uid' => $uid], true);
+	}
+}
diff --git a/src/Model/Post/User.php b/src/Model/Post/User.php
index 6c2176656..dc53b726e 100644
--- a/src/Model/Post/User.php
+++ b/src/Model/Post/User.php
@@ -29,7 +29,7 @@ use Friendica\Database\DBStructure;
 class User
 {
 	/**
-	 * Insert a new URI user entry
+	 * Insert a new post user entry
 	 *
 	 * @param integer $uri_id
 	 * @param integer $uid
@@ -66,7 +66,7 @@ class User
 	}
 
 	/**
-	 * Update a URI user entry
+	 * Update a post user entry
 	 *
 	 * @param integer $uri_id
 	 * @param integer $uid
diff --git a/src/Model/UserItem.php b/src/Model/Post/UserNotification.php
similarity index 78%
rename from src/Model/UserItem.php
rename to src/Model/Post/UserNotification.php
index b4346c221..9173cfbe2 100644
--- a/src/Model/UserItem.php
+++ b/src/Model/Post/UserNotification.php
@@ -19,17 +19,23 @@
  *
  */
 
-namespace Friendica\Model;
+namespace Friendica\Model\Post;
 
+use \BadMethodCallException;
 use Friendica\Core\Logger;
 use Friendica\Core\Hook;
+use Friendica\Database\Database;
 use Friendica\Database\DBA;
+use Friendica\Database\DBStructure;
 use Friendica\DI;
+use Friendica\Model\Contact;
+use Friendica\Model\Post;
 use Friendica\Util\Strings;
 use Friendica\Model\Tag;
 use Friendica\Protocol\Activity;
 
-class UserItem
+
+class UserNotification
 {
 	// Notification types
 	const NOTIF_NONE = 0;
@@ -42,18 +48,89 @@ class UserItem
 	const NOTIF_DIRECT_THREAD_COMMENT = 64;
 	const NOTIF_SHARED = 128;
 
+
+	/**
+	 * Insert a new user notification entry
+	 *
+	 * @param integer $uri_id
+	 * @param integer $uid
+	 * @param array   $fields
+	 * @return bool   success
+	 * @throws \Exception
+	 */
+	public static function insert(int $uri_id, int $uid, array $data = [])
+	{
+		if (empty($uri_id)) {
+			throw new BadMethodCallException('Empty URI_id');
+		}
+
+		$fields = DBStructure::getFieldsForTable('post-user-notification', $data);
+
+		// Additionally assign the key fields
+		$fields['uri-id'] = $uri_id;
+		$fields['uid'] = $uid;
+
+		return DBA::insert('post-user-notification', $fields, Database::INSERT_IGNORE);
+	}
+
+	/**
+	 * Update a user notification entry
+	 *
+	 * @param integer $uri_id
+	 * @param integer $uid
+	 * @param array   $data
+	 * @param bool    $insert_if_missing
+	 * @return bool
+	 * @throws \Exception
+	 */
+	public static function update(int $uri_id, int $uid, array $data = [], bool $insert_if_missing = false)
+	{
+		if (empty($uri_id)) {
+			throw new BadMethodCallException('Empty URI_id');
+		}
+
+		$fields = DBStructure::getFieldsForTable('post-user-notification', $data);
+
+		// Remove the key fields
+		unset($fields['uri-id']);
+		unset($fields['uid']);
+
+		if (empty($fields)) {
+			return true;
+		}
+
+		return DBA::update('post-user-notification', $fields, ['uri-id' => $uri_id, 'uid' => $uid], $insert_if_missing ? true : []);
+	}
+
+	/**
+	 * Delete a row from the post-user-notification table
+	 *
+	 * @param array        $conditions Field condition(s)
+	 * @param array        $options
+	 *                           - cascade: If true we delete records in other tables that depend on the one we're deleting through
+	 *                           relations (default: true)
+	 *
+	 * @return boolean was the delete successful?
+	 * @throws \Exception
+	 */
+	public static function delete(array $conditions, array $options = [])
+	{
+		return DBA::delete('post-user-notification', $conditions, $options);
+	}
+
 	/**
 	 * Checks an item for notifications and sets the "notification-type" field
 	 * @ToDo:
 	 * - Check for mentions in posts with "uid=0" where the user hadn't interacted before
 	 *
-	 * @param int $iid Item ID
+	 * @param int $uri_id URI ID
+	 * @param int $uid    user ID
 	 */
-	public static function setNotification(int $iid)
+	public static function setNotification(int $uri_id, int $uid)
 	{
 		$fields = ['id', 'uri-id', 'parent-uri-id', 'uid', 'body', 'parent', 'gravity',
-			'private', 'contact-id', 'thr-parent', 'parent-uri', 'author-id', 'verb'];
-		$item = Post::selectFirst($fields, ['id' => $iid, 'origin' => false]);
+			'private', 'contact-id', 'thr-parent', 'parent-uri-id', 'parent-uri', 'author-id', 'verb'];
+		$item = Post::selectFirst($fields, ['uri-id' => $uri_id, 'uid' => $uid, 'origin' => false]);
 		if (!DBA::isResult($item)) {
 			return;
 		}
@@ -73,7 +150,7 @@ class UserItem
 		// Add every user who participated so far in this thread
 		// This can only happen with participations on global items. (means: uid = 0) 
 		$users = DBA::p("SELECT DISTINCT(`contact-uid`) AS `uid` FROM `post-view`
-			WHERE `contact-uid` != 0 AND `parent` IN (SELECT `parent` FROM `post-view` WHERE `id` = ?)", $iid);
+			WHERE `contact-uid` != 0 AND `parent-uri-id` = ? AND `uid` = ?", $item['parent-uri-id'], $uid);
 		while ($user = DBA::fetch($users)) {
 			$uids[] = $user['uid'];
 		}
@@ -92,8 +169,7 @@ class UserItem
 	 */
 	private static function setNotificationForUser(array $item, int $uid)
 	{
-		$thread = Post::selectFirstThreadForUser($uid, ['ignored'], ['iid' => $item['parent'], 'deleted' => false]);
-		if (!empty($thread['ignored'])) {
+		if (Post\ThreadUser::getIgnored($item['parent-uri-id'], $uid)) {
 			return;
 		}
 
@@ -153,11 +229,11 @@ class UserItem
 			return;
 		}
 
-		Logger::info('Set notification', ['iid' => $item['id'], 'uid' => $uid, 'notification-type' => $notification_type]);
+		Logger::info('Set notification', ['iid' => $item['id'], 'uri-id' => $item['uri-id'], 'uid' => $uid, 'notification-type' => $notification_type]);
 
 		$fields = ['notification-type' => $notification_type];
 		Post\User::update($item['uri-id'], $uid, $fields);
-		DBA::update('user-item', $fields, ['iid' => $item['id'], 'uid' => $uid], true);
+		self::update($item['uri-id'], $uid, $fields, true);
 	}
 
 	/**
diff --git a/src/Module/Item/Ignore.php b/src/Module/Item/Ignore.php
index 668e49310..22d676b22 100644
--- a/src/Module/Item/Ignore.php
+++ b/src/Module/Item/Ignore.php
@@ -49,27 +49,17 @@ class Ignore extends BaseModule
 
 		$dba = DI::dba();
 
-		$thread = Post::selectFirstThreadForUser(local_user(), ['uid', 'ignored'], ['iid' => $itemId]);
+		$thread = Post::selectFirst(['uri-id', 'uid'], ['id' => $itemId, 'gravity' => GRAVITY_PARENT]);
 		if (!$dba->isResult($thread)) {
 			throw new HTTPException\NotFoundException();
 		}
 
-		// Numeric values are needed for the json output further below
-		$ignored = !empty($thread['ignored']) ? 0 : 1;
+		$ignored = !Post\ThreadUser::getIgnored($thread['uri-id'], local_user());
 
-		switch ($thread['uid'] ?? 0) {
-			// if the thread is from the current user
-			case local_user():
-				$dba->update('thread', ['ignored' => $ignored], ['iid' => $itemId]);
-				break;
-			// 0 (null will get transformed to 0) => it's a public post
-			case 0:
-				$dba->update('user-item', ['ignored' => $ignored], ['iid' => $itemId, 'uid' => local_user()], true);
-				break;
-			// Throws a BadRequestException and not a ForbiddenException on purpose
-			// Avoids harvesting existing, but forbidden IIDs (security issue)
-			default:
-				throw new HTTPException\BadRequestException();
+		if (in_array($thread['uid'], [0, local_user()])) {
+			Post\ThreadUser::setIgnored($thread['uri-id'], local_user(), $ignored);
+		} else {
+			throw new HTTPException\BadRequestException();
 		}
 
 		// See if we've been passed a return path to redirect to
diff --git a/src/Module/Item/Pin.php b/src/Module/Item/Pin.php
index d99b1a345..08c751de2 100644
--- a/src/Module/Item/Pin.php
+++ b/src/Module/Item/Pin.php
@@ -24,8 +24,9 @@ namespace Friendica\Module\Item;
 use Friendica\BaseModule;
 use Friendica\Core\Session;
 use Friendica\Core\System;
+use Friendica\Database\DBA;
 use Friendica\DI;
-use Friendica\Model\Item;
+use Friendica\Model\Post;
 use Friendica\Network\HTTPException;
 
 /**
@@ -47,9 +48,18 @@ class Pin extends BaseModule
 
 		$itemId = intval($parameters['id']);
 
-		$pinned = !Item::getPinned($itemId, local_user());
+		$item = Post::selectFirst(['uri-id', 'uid'], ['id' => $itemId]);
+		if (!DBA::isResult($item)) {
+			throw new HTTPException\NotFoundException();
+		}
 
-		Item::setPinned($itemId, local_user(), $pinned);
+		if (!in_array($item['uid'], [0, local_user()])) {
+			throw new HttpException\ForbiddenException($l10n->t('Access denied.'));
+		}
+
+		$pinned = !Post\ThreadUser::getPinned($item['uri-id'], local_user());
+
+		Post\ThreadUser::setPinned($item['uri-id'], local_user(), $pinned);
 
 		// See if we've been passed a return path to redirect to
 		$return_path = $_REQUEST['return'] ?? '';
diff --git a/src/Object/Post.php b/src/Object/Post.php
index 34f46f797..d2c0b31e1 100644
--- a/src/Object/Post.php
+++ b/src/Object/Post.php
@@ -307,17 +307,15 @@ class Post
 
 		if ($this->isToplevel()) {
 			if(local_user()) {
-				$thread = PostModel::selectFirstThreadForUser(local_user(), ['ignored'], ['iid' => $item['id']]);
-				if (DBA::isResult($thread)) {
-					$ignore = [
-						'do'        => DI::l10n()->t("ignore thread"),
-						'undo'      => DI::l10n()->t("unignore thread"),
-						'toggle'    => DI::l10n()->t("toggle ignore status"),
-						'classdo'   => $thread['ignored'] ? "hidden" : "",
-						'classundo' => $thread['ignored'] ? "" : "hidden",
-						'ignored'   => DI::l10n()->t('ignored'),
-					];
-				}
+				$ignored = PostModel\ThreadUser::getIgnored($item['uri-id'], local_user());
+				$ignore = [
+					'do'        => DI::l10n()->t("ignore thread"),
+					'undo'      => DI::l10n()->t("unignore thread"),
+					'toggle'    => DI::l10n()->t("toggle ignore status"),
+					'classdo'   => $ignored ? "hidden" : "",
+					'classundo' => $ignored ? "" : "hidden",
+					'ignored'   => DI::l10n()->t('ignored'),
+				];
 
 				if ($conv->getProfileOwner() == local_user() && ($item['uid'] != 0)) {
 					if ($origin) {
diff --git a/static/dbstructure.config.php b/static/dbstructure.config.php
index d0c35e4f8..6b8aba3ac 100644
--- a/static/dbstructure.config.php
+++ b/static/dbstructure.config.php
@@ -55,7 +55,7 @@
 use Friendica\Database\DBA;
 
 if (!defined('DB_UPDATE_VERSION')) {
-	define('DB_UPDATE_VERSION', 1396);
+	define('DB_UPDATE_VERSION', 1397);
 }
 
 return [
@@ -750,7 +750,6 @@ return [
 			"guid" => ["type" => "varchar(255)", "not null" => "1", "default" => "", "comment" => "A unique identifier for this item"],
 			"uri" => ["type" => "varchar(255)", "not null" => "1", "default" => "", "comment" => ""],
 			"uri-id" => ["type" => "int unsigned", "foreign" => ["item-uri" => "id"], "comment" => "Id of the item-uri table entry that contains the item uri"],
-			"uri-hash" => ["type" => "varchar(80)", "not null" => "1", "default" => "", "comment" => "RIPEMD-128 hash from uri"],
 			"parent" => ["type" => "int unsigned", "relation" => ["item" => "id"], "comment" => "item.id of the parent to this item if it is a reply of some form; otherwise this must be set to the id of this item"],
 			"parent-uri" => ["type" => "varchar(255)", "not null" => "1", "default" => "", "comment" => "uri of the top-level parent to this item"],
 			"parent-uri-id" => ["type" => "int unsigned", "foreign" => ["item-uri" => "id"], "comment" => "Id of the item-uri table that contains the top-level parent uri"],
@@ -774,21 +773,26 @@ return [
 			"visible" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => ""],
 			"moderated" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => ""],
 			"deleted" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => "item has been deleted"],
-			// User specific fields. Eventually they will move to user-item
+			// Part of "post-user". Will be deprecated in a later step
 			"uid" => ["type" => "mediumint unsigned", "not null" => "1", "default" => "0", "foreign" => ["user" => "uid"], "comment" => "Owner id which owns this copy of the item"],
 			"contact-id" => ["type" => "int unsigned", "not null" => "1", "default" => "0", "foreign" => ["contact" => "id"], "comment" => "contact.id"],
-			"wall" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => "This item was posted to the wall of uid"],
-			"origin" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => "item originated at this site"],
-			"pubmail" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => ""],
-			"starred" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => "item has been favourited"],
 			"unseen" => ["type" => "boolean", "not null" => "1", "default" => "1", "comment" => "item has not been seen"],
-			"mention" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => "The owner of this item was mentioned in it"],
-			"forum_mode" => ["type" => "tinyint unsigned", "not null" => "1", "default" => "0", "comment" => ""],
+			"origin" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => "item originated at this site"],
 			"psid" => ["type" => "int unsigned", "foreign" => ["permissionset" => "id", "on delete" => "restrict"], "comment" => "ID of the permission set of this post"],
+			// Part of "post-thread-user". Will be deprecated in a later step
+			"starred" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => "item has been favourited"],
+			"wall" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => "This item was posted to the wall of uid"],
+			"pubmail" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => ""],
+			"forum_mode" => ["type" => "tinyint unsigned", "not null" => "1", "default" => "0", "comment" => ""],
 			// It has to be decided whether these fields belong to the user or the structure
-			"resource-id" => ["type" => "varchar(32)", "not null" => "1", "default" => "", "comment" => "Used to link other tables to items, it identifies the linked resource (e.g. photo) and if set must also set resource_type"],
 			"event-id" => ["type" => "int unsigned", "relation" => ["event" => "id"], "comment" => "Used to link to the event.id"],
+			// Check deprecation status
+			"type" => ["type" => "varchar(20)", "comment" => ""],
+			"bookmark" => ["type" => "boolean", "comment" => ""],
+			"mention" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => "The owner of this item was mentioned in it"],
 			// Deprecated fields. Will be removed in upcoming versions
+			"resource-id" => ["type" => "varchar(32)", "comment" => "Deprecated"],
+			"uri-hash" => ["type" => "varchar(80)", "comment" => "Deprecated"],
 			"iaid" => ["type" => "int unsigned", "comment" => "Deprecated"],
 			"icid" => ["type" => "int unsigned", "comment" => "Deprecated"],
 			"attach" => ["type" => "mediumtext", "comment" => "Deprecated"],
@@ -798,8 +802,6 @@ return [
 			"deny_gid" => ["type" => "mediumtext", "comment" => "Deprecated"],
 			"postopts" => ["type" => "text", "comment" => "Deprecated"],
 			"inform" => ["type" => "mediumtext", "comment" => "Deprecated"],
-			"type" => ["type" => "varchar(20)", "comment" => "Deprecated"],
-			"bookmark" => ["type" => "boolean", "comment" => "Deprecated"],
 			"file" => ["type" => "mediumtext", "comment" => "Deprecated"],
 			"location" => ["type" => "varchar(255)", "comment" => "Deprecated"],
 			"coord" => ["type" => "varchar(255)", "comment" => "Deprecated"],
@@ -1029,20 +1031,6 @@ return [
 			"created" => ["created"],
 		]
 	],
-	"participation" => [
-		"comment" => "Storage for participation messages from Diaspora",
-		"fields" => [
-			"iid" => ["type" => "int unsigned", "not null" => "1", "primary" => "1", "foreign" => ["item" => "id"], "comment" => ""],
-			"server" => ["type" => "varchar(60)", "not null" => "1", "primary" => "1", "comment" => ""],
-			"cid" => ["type" => "int unsigned", "not null" => "1", "foreign" => ["contact" => "id"], "comment" => ""],
-			"fid" => ["type" => "int unsigned", "not null" => "1", "foreign" => ["fcontact" => "id"], "comment" => ""],
-		],
-		"indexes" => [
-			"PRIMARY" => ["iid", "server"],
-			"cid" => ["cid"],
-			"fid" => ["fid"]
-		]
-	],
 	"pconfig" => [
 		"comment" => "personal (per user) configuration storage",
 		"fields" => [
@@ -1193,6 +1181,25 @@ return [
 			"cid" => ["cid"]
 		]
 	],
+	"post-thread-user" => [
+		"comment" => "Thread related data per user",
+		"fields" => [
+			"uri-id" => ["type" => "int unsigned", "not null" => "1", "primary" => "1", "foreign" => ["item-uri" => "id"], "comment" => "Id of the item-uri table entry that contains the item uri"],
+			"uid" => ["type" => "mediumint unsigned", "not null" => "1", "default" => "0", "primary" => "1", "foreign" => ["user" => "uid"], "comment" => "Owner id which owns this copy of the item"],
+			"pinned" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => "The thread is pinned on the profile page"],
+			"starred" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => ""],
+			"ignored" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => "Ignore updates for this thread"],
+			"wall" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => "This item was posted to the wall of uid"],
+			"pubmail" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => ""],
+			"forum_mode" => ["type" => "tinyint unsigned", "not null" => "1", "default" => "0", "comment" => ""]
+		],
+		"indexes" => [
+			"PRIMARY" => ["uid", "uri-id"],
+			"uid_wall" => ["uid", "wall"],
+			"uid_pinned" => ["uid", "pinned"],
+			"uri-id" => ["uri-id"],
+		]
+	],
 	"post-user" => [
 		"comment" => "User specific post data",
 		"fields" => [
@@ -1215,6 +1222,18 @@ return [
 			"psid" => ["psid"],
 		],
 	],
+	"post-user-notification" => [
+		"comment" => "User post notifications",
+		"fields" => [
+			"uri-id" => ["type" => "int unsigned", "not null" => "1", "primary" => "1", "foreign" => ["item-uri" => "id"], "comment" => "Id of the item-uri table entry that contains the item uri"],
+			"uid" => ["type" => "mediumint unsigned", "not null" => "1", "primary" => "1", "foreign" => ["user" => "uid"], "comment" => "Owner id which owns this copy of the item"],
+			"notification-type" => ["type" => "tinyint unsigned", "not null" => "1", "default" => "0", "comment" => ""],
+		],
+		"indexes" => [
+			"PRIMARY" => ["uid", "uri-id"],
+			"uri-id" => ["uri-id"],
+		],
+	],
 	"process" => [
 		"comment" => "Currently running system processes",
 		"fields" => [
@@ -1474,22 +1493,6 @@ return [
 			"cid" => ["cid"],
 		]
 	],
-	"user-item" => [
-		"comment" => "User specific item data",
-		"fields" => [
-			"iid" => ["type" => "int unsigned", "not null" => "1", "default" => "0", "primary" => "1", "foreign" => ["item" => "id"], "comment" => "Item id"],
-			"uid" => ["type" => "mediumint unsigned", "not null" => "1", "default" => "0", "primary" => "1", "foreign" => ["user" => "uid"], "comment" => "User id"],
-			"hidden" => ["type" => "boolean", "not null" => "1", "default" => "0", "comment" => "Marker to hide an item from the user"],
-			"ignored" => ["type" => "boolean", "comment" => "Ignore this thread if set"],
-			"pinned" => ["type" => "boolean", "comment" => "The item is pinned on the profile page"],
-			"notification-type" => ["type" => "tinyint unsigned", "not null" => "1", "default" => "0", "comment" => ""],
-		],
-		"indexes" => [
-			"PRIMARY" => ["uid", "iid"],
-			"uid_pinned" => ["uid", "pinned"],
-			"iid_uid" => ["iid", "uid"]
-		]
-	],
 	"worker-ipc" => [
 		"comment" => "Inter process communication between the frontend and the worker",
 		"fields" => [
diff --git a/static/dbview.config.php b/static/dbview.config.php
index c7f52a5cf..088e426ba 100644
--- a/static/dbview.config.php
+++ b/static/dbview.config.php
@@ -395,13 +395,13 @@
 		"query" => "FROM `item`
 			INNER JOIN `thread` ON `thread`.`iid` = `item`.`parent`
 			STRAIGHT_JOIN `contact` ON `contact`.`id` = `thread`.`contact-id`
-			LEFT JOIN `user-item` ON `user-item`.`iid` = `item`.`id` AND `user-item`.`uid` = `thread`.`uid`
+			LEFT JOIN `post-user` ON `post-user`.`uri-id` = `item`.`uri-id` AND `post-user`.`uid` = `thread`.`uid`
 			LEFT JOIN `user-contact` AS `author` ON `author`.`uid` = `thread`.`uid` AND `author`.`cid` = `thread`.`author-id`
 			LEFT JOIN `user-contact` AS `owner` ON `owner`.`uid` = `thread`.`uid` AND `owner`.`cid` = `thread`.`owner-id`
 			LEFT JOIN `contact` AS `ownercontact` ON `ownercontact`.`id` = `thread`.`owner-id`
 			WHERE `thread`.`visible` AND NOT `thread`.`deleted` AND NOT `thread`.`moderated`
 			AND (NOT `contact`.`readonly` AND NOT `contact`.`blocked` AND NOT `contact`.`pending`)
-			AND (`user-item`.`hidden` IS NULL OR NOT `user-item`.`hidden`)
+			AND (`post-user`.`hidden` IS NULL OR NOT `post-user`.`hidden`)
 			AND (`author`.`blocked` IS NULL OR NOT `author`.`blocked`)
 			AND (`owner`.`blocked` IS NULL OR NOT `owner`.`blocked`)"
 	],
@@ -424,13 +424,13 @@
 		"query" => "FROM `thread`
 			STRAIGHT_JOIN `contact` ON `contact`.`id` = `thread`.`contact-id`
 			STRAIGHT_JOIN `item` ON `item`.`id` = `thread`.`iid`
-			LEFT JOIN `user-item` ON `user-item`.`iid` = `item`.`id` AND `user-item`.`uid` = `thread`.`uid`
+			LEFT JOIN `post-user` ON `post-user`.`uri-id` = `item`.`uri-id` AND `post-user`.`uid` = `thread`.`uid`
 			LEFT JOIN `user-contact` AS `author` ON `author`.`uid` = `thread`.`uid` AND `author`.`cid` = `thread`.`author-id`
 			LEFT JOIN `user-contact` AS `owner` ON `owner`.`uid` = `thread`.`uid` AND `owner`.`cid` = `thread`.`owner-id`
 			LEFT JOIN `contact` AS `ownercontact` ON `ownercontact`.`id` = `thread`.`owner-id`
 			WHERE `thread`.`visible` AND NOT `thread`.`deleted` AND NOT `thread`.`moderated`
 			AND (NOT `contact`.`readonly` AND NOT `contact`.`blocked` AND NOT `contact`.`pending`)
-			AND (`user-item`.`hidden` IS NULL OR NOT `user-item`.`hidden`)
+			AND (`post-user`.`hidden` IS NULL OR NOT `post-user`.`hidden`)
 			AND (`author`.`blocked` IS NULL OR NOT `author`.`blocked`)
 			AND (`owner`.`blocked` IS NULL OR NOT `owner`.`blocked`)"
 	],
diff --git a/update.php b/update.php
index 3e9292f2e..94029065b 100644
--- a/update.php
+++ b/update.php
@@ -466,7 +466,7 @@ function pre_update_1364()
 		return Update::FAILED;
 	}
 
-	if (!DBA::e("DELETE FROM `user-item` WHERE NOT `uid` IN (SELECT `uid` FROM `user`)")) {
+	if (DBStructure::existsTable('user-item') && !DBA::e("DELETE FROM `user-item` WHERE NOT `uid` IN (SELECT `uid` FROM `user`)")) {
 		return Update::FAILED;
 	}
 
@@ -490,10 +490,6 @@ function pre_update_1364()
 		return Update::FAILED;
 	}
 
-	if (!DBA::e("DELETE FROM `participation` WHERE NOT `cid` IN (SELECT `id` FROM `contact`)")) {
-		return Update::FAILED;
-	}
-
 	if (!DBA::e("DELETE FROM `profile_check` WHERE NOT `cid` IN (SELECT `id` FROM `contact`)")) {
 		return Update::FAILED;
 	}
@@ -502,10 +498,6 @@ function pre_update_1364()
 		return Update::FAILED;
 	}
 
-	if (!DBA::e("DELETE FROM `participation` WHERE NOT `fid` IN (SELECT `id` FROM `fcontact`)")) {
-		return Update::FAILED;
-	}
-
 	if (!DBA::e("DELETE FROM `group_member` WHERE NOT `gid` IN (SELECT `id` FROM `group`)")) {
 		return Update::FAILED;
 	}
@@ -514,11 +506,7 @@ function pre_update_1364()
 		return Update::FAILED;
 	}
 
-	if (!DBA::e("DELETE FROM `participation` WHERE NOT `iid` IN (SELECT `id` FROM `item`)")) {
-		return Update::FAILED;
-	}
-
-	if (!DBA::e("DELETE FROM `user-item` WHERE NOT `iid` IN (SELECT `id` FROM `item`)")) {
+	if (DBStructure::existsTable('user-item') && !DBA::e("DELETE FROM `user-item` WHERE NOT `iid` IN (SELECT `id` FROM `item`)")) {
 		return Update::FAILED;
 	}
 
@@ -686,7 +674,7 @@ function update_1395()
 		return Update::FAILED;
 	}
 
-	if (!DBA::e("INSERT INTO `post-user`(`uri-id`, `uid`, `hidden`, `notification-type`)
+	if (DBStructure::existsTable('user-item') && !DBA::e("INSERT INTO `post-user`(`uri-id`, `uid`, `hidden`, `notification-type`)
 		SELECT `uri-id`, `user-item`.`uid`, `hidden`,`notification-type` FROM `user-item`
 			INNER JOIN `item` ON `item`.`id` = `user-item`.`iid`
 		ON DUPLICATE KEY UPDATE `hidden` = `user-item`.`hidden`, `notification-type` = `user-item`.`notification-type`")) {
@@ -713,4 +701,37 @@ function update_1396()
 		return Update::FAILED;
 	}
 	return Update::SUCCESS;
-}
\ No newline at end of file
+}
+
+function update_1397()
+{
+	if (!DBA::e("INSERT INTO `post-user-notification`(`uri-id`, `uid`, `notification-type`)
+		SELECT `uri-id`, `uid`, `notification-type` FROM `post-user` WHERE `notification-type` != 0
+		ON DUPLICATE KEY UPDATE `uri-id` = `post-user`.`uri-id`, `uid` = `post-user`.`uid`, `notification-type` = `post-user`.`notification-type`")) {
+		return Update::FAILED;
+	}
+
+	if (!DBStructure::existsTable('user-item')) {
+		return Update::SUCCESS;
+	}
+
+	if (!DBA::e("INSERT INTO `post-user-notification`(`uri-id`, `uid`, `notification-type`)
+		SELECT `uri-id`, `user-item`.`uid`, `notification-type` FROM `user-item`
+			INNER JOIN `item` ON `item`.`id` = `user-item`.`iid` WHERE `notification-type` != 0
+		ON DUPLICATE KEY UPDATE `notification-type` = `user-item`.`notification-type`")) {
+		return Update::FAILED;
+	}
+
+	if (!DBStructure::existsTable('thread')) {
+		return Update::SUCCESS;
+	}
+
+	if (!DBA::e("INSERT IGNORE INTO `post-thread-user`(`uri-id`, `uid`, `pinned`, `starred`, `ignored`, `wall`, `pubmail`, `forum_mode`)
+		SELECT `thread`.`uri-id`, `thread`.`uid`, `user-item`.`pinned`, `thread`.`starred`,
+			`thread`.`ignored`, `thread`.`wall`, `thread`.`pubmail`, `thread`.`forum_mode`
+		FROM `thread` LEFT JOIN `user-item` ON `user-item`.`iid` = `thread`.`iid`")) {
+		return Update::FAILED;
+	}
+
+	return Update::SUCCESS;
+}