diff --git a/papers/format.md b/papers/format.md
index bb0085f5..6d463a89 100644
--- a/papers/format.md
+++ b/papers/format.md
@@ -32,6 +32,8 @@ these fields are 0 in format versions prior to 100 (0.6pre1).
 
 the format versions are:
 
+- 118: Furnace dev118
+- 117: Furnace dev117
 - 116: Furnace 0.6pre1.5
 - 115: Furnace dev115
 - 114: Furnace dev114
@@ -905,6 +907,7 @@ size | description
   1  | attack
   1  | decay
   1  | sustain
+     | - bit 3: sustain mode (>=118)
   1  | release
  --- | **macro speeds/delays** (>=111)
   1  | volume macro speed
diff --git a/src/engine/engine.h b/src/engine/engine.h
index 2219b6e2..19d86905 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -46,8 +46,8 @@
 #define BUSY_BEGIN_SOFT softLocked=true; isBusy.lock();
 #define BUSY_END isBusy.unlock(); softLocked=false;
 
-#define DIV_VERSION "dev117"
-#define DIV_ENGINE_VERSION 117
+#define DIV_VERSION "dev118"
+#define DIV_ENGINE_VERSION 118
 // for imports
 #define DIV_VERSION_MOD 0xff01
 #define DIV_VERSION_FC 0xff02
diff --git a/src/engine/instrument.cpp b/src/engine/instrument.cpp
index e944fdbf..a78bb8ff 100644
--- a/src/engine/instrument.cpp
+++ b/src/engine/instrument.cpp
@@ -559,13 +559,12 @@ void DivInstrument::putInsData(SafeWriter* w) {
   w->writeC(es5506.envelope.k2Slow);
   
   // SNES
-  // @tildearrow please update this
   w->writeC(snes.useEnv);
-  w->writeC(0);
-  w->writeC(0);
+  w->writeC(snes.gainMode);
+  w->writeC(snes.gain);
   w->writeC(snes.a);
   w->writeC(snes.d);
-  w->writeC(snes.s);
+  w->writeC((snes.s&7)|(snes.sus?8:0));
   w->writeC(snes.r);
 
   // macro speed/delay
@@ -1259,11 +1258,13 @@ DivDataErrors DivInstrument::readInsData(SafeReader& reader, short version) {
   // SNES
   if (version>=109) {
     snes.useEnv=reader.readC();
-    reader.readC();
-    reader.readC();
+    snes.gainMode=(DivInstrumentSNES::GainMode)reader.readC();
+    snes.gain=reader.readC();
     snes.a=reader.readC();
     snes.d=reader.readC();
     snes.s=reader.readC();
+    snes.sus=snes.s&8;
+    snes.s&=7;
     snes.r=reader.readC();
   }
 
diff --git a/src/engine/instrument.h b/src/engine/instrument.h
index 01323d90..a8283430 100644
--- a/src/engine/instrument.h
+++ b/src/engine/instrument.h
@@ -527,12 +527,13 @@ struct DivInstrumentSNES {
     GAIN_MODE_INC_LINEAR=6,
     GAIN_MODE_INC_INVLOG=7
   };
-  bool useEnv;
+  bool useEnv, sus;
   GainMode gainMode;
   unsigned char gain;
   unsigned char a, d, s, r;
   DivInstrumentSNES():
     useEnv(true),
+    sus(false),
     gainMode(GAIN_MODE_DIRECT),
     gain(127),
     a(15),
diff --git a/src/engine/platform/snes.cpp b/src/engine/platform/snes.cpp
index 0454ed35..5bd28b19 100644
--- a/src/engine/platform/snes.cpp
+++ b/src/engine/platform/snes.cpp
@@ -208,7 +208,9 @@ void DivPlatformSNES::tick(bool sysTick) {
         chan[i].keyOn=false;
       }
       if (chan[i].keyOff) {
-        koff|=(1<<i);
+        if (!chan[i].state.sus) {
+          koff|=(1<<i);
+        }
         chan[i].keyOff=false;
       }
       if (chan[i].freqChanged) {
@@ -296,6 +298,9 @@ int DivPlatformSNES::dispatch(DivCommand c) {
       }
       if (chan[c.chan].insChanged) {
         chan[c.chan].state=ins->snes;
+      }
+      chan[c.chan].active=true;
+      if (chan[c.chan].insChanged || chan[c.chan].state.sus) {
         writeEnv(c.chan);
       }
       if (c.value!=DIV_NOTE_NULL) {
@@ -303,19 +308,30 @@ int DivPlatformSNES::dispatch(DivCommand c) {
         chan[c.chan].freqChanged=true;
         chan[c.chan].note=c.value;
       }
-      chan[c.chan].active=true;
       chan[c.chan].keyOn=true;
       chan[c.chan].macroInit(ins);
       chan[c.chan].insChanged=false;
       break;
     }
     case DIV_CMD_NOTE_OFF:
-      chan[c.chan].sample=-1;
       chan[c.chan].active=false;
       chan[c.chan].keyOff=true;
-      chan[c.chan].macroInit(NULL);
+      chan[c.chan].keyOn=false;
+      if (chan[c.chan].state.sus) {
+        writeEnv(c.chan);
+      } else {
+        chan[c.chan].macroInit(NULL);
+      }
       break;
     case DIV_CMD_NOTE_OFF_ENV:
+      chan[c.chan].active=false;
+      chan[c.chan].keyOff=true;
+      chan[c.chan].keyOn=false;
+      if (chan[c.chan].state.sus) {
+        writeEnv(c.chan);
+      }
+      chan[c.chan].std.release();
+      break;
     case DIV_CMD_ENV_RELEASE:
       chan[c.chan].std.release();
       break;
@@ -537,7 +553,11 @@ void DivPlatformSNES::writeOutVol(int ch) {
 void DivPlatformSNES::writeEnv(int ch) {
   if (chan[ch].state.useEnv) {
     chWrite(ch,5,chan[ch].state.a|(chan[ch].state.d<<4)|0x80);
-    chWrite(ch,6,chan[ch].state.r|(chan[ch].state.s<<5));
+    if (chan[ch].state.sus && chan[ch].active) {
+      chWrite(ch,6,chan[ch].state.s<<5);
+    } else {
+      chWrite(ch,6,chan[ch].state.r|(chan[ch].state.s<<5));
+    }
   } else {
     chWrite(ch,5,0);
     switch (chan[ch].state.gainMode) {
diff --git a/src/gui/insEdit.cpp b/src/gui/insEdit.cpp
index 15434a80..2ab022dd 100644
--- a/src/gui/insEdit.cpp
+++ b/src/gui/insEdit.cpp
@@ -4066,6 +4066,7 @@ void FurnaceGUI::drawInsEdit() {
 
               ImGui::EndTable();
             }
+            ImGui::Checkbox("Make sustain effective",&ins->snes.sus);
           } else {
             if (ImGui::BeginTable("SNESGainParams",3,ImGuiTableFlags_NoHostExtendX)) {
               ImGui::TableSetupColumn("c0",ImGuiTableColumnFlags_WidthFixed);