diff --git a/src/sfizz/Config.h b/src/sfizz/Config.h
index a551b4f6..9a0bb82a 100644
--- a/src/sfizz/Config.h
+++ b/src/sfizz/Config.h
@@ -183,6 +183,11 @@ namespace config {
      *
      */
     constexpr int playheadMovedFrames { 16 };
+    /**
+     * @brief Max number of voices to start on release pedal up
+     *
+     */
+    constexpr unsigned delayedReleaseVoices { 16 };
 } // namespace config
 
 } // namespace sfz
diff --git a/src/sfizz/Defaults.cpp b/src/sfizz/Defaults.cpp
index 4deee968..2d2886f0 100644
--- a/src/sfizz/Defaults.cpp
+++ b/src/sfizz/Defaults.cpp
@@ -61,7 +61,9 @@ UInt16Spec ccNumber { 0, {0, config::numCCs}, 0 };
 UInt16Spec smoothCC { 0, {0, 100}, kPermissiveUpperBound };
 UInt8Spec curveCC { 0, {0, 255}, 0 };
 UInt8Spec sustainCC { 64, {0, 127}, 0 };
+UInt8Spec sostenutoCC { 66, {0, 127}, 0 };
 FloatSpec sustainThreshold { 1.0f, {0.0f, 127.0f}, kNormalizeMidi|kPermissiveBounds };
+FloatSpec sostenutoThreshold { 1.0f, {0.0f, 127.0f}, kNormalizeMidi|kPermissiveBounds };
 BoolSpec checkSustain { true, {0, 1}, kEnforceBounds };
 BoolSpec checkSostenuto { true, {0, 1}, kEnforceBounds };
 FloatSpec loBPM { 0.0f, {0.0f, 500.0f}, kPermissiveBounds };
diff --git a/src/sfizz/Defaults.h b/src/sfizz/Defaults.h
index 28dba5fa..70735abf 100644
--- a/src/sfizz/Defaults.h
+++ b/src/sfizz/Defaults.h
@@ -161,9 +161,11 @@ namespace Default
     extern const OpcodeSpec<uint8_t> curveCC;
     extern const OpcodeSpec<uint16_t> smoothCC;
     extern const OpcodeSpec<uint8_t> sustainCC;
+    extern const OpcodeSpec<uint8_t> sostenutoCC;
     extern const OpcodeSpec<bool> checkSustain;
     extern const OpcodeSpec<bool> checkSostenuto;
     extern const OpcodeSpec<float> sustainThreshold;
+    extern const OpcodeSpec<float> sostenutoThreshold;
     extern const OpcodeSpec<float> loBPM;
     extern const OpcodeSpec<float> hiBPM;
     extern const OpcodeSpec<uint8_t> sequence;
diff --git a/src/sfizz/MidiState.cpp b/src/sfizz/MidiState.cpp
index 938fba1e..c8df355a 100644
--- a/src/sfizz/MidiState.cpp
+++ b/src/sfizz/MidiState.cpp
@@ -23,6 +23,7 @@ void sfz::MidiState::noteOnEvent(int delay, int noteNumber, float velocity) noex
         noteOnTimes[noteNumber] = internalClock + static_cast<unsigned>(delay);
         lastNotePlayed = noteNumber;
         activeNotes++;
+        noteStates[noteNumber] = true;
     }
 
 }
@@ -37,6 +38,7 @@ void sfz::MidiState::noteOffEvent(int delay, int noteNumber, float velocity) noe
         noteOffTimes[noteNumber] = internalClock + static_cast<unsigned>(delay);
         if (activeNotes > 0)
             activeNotes--;
+        noteStates[noteNumber] = false;
     }
 
 }
@@ -181,6 +183,7 @@ void sfz::MidiState::reset() noexcept
     activeNotes = 0;
     internalClock = 0;
     lastNotePlayed = 0;
+    noteStates.reset();
     absl::c_fill(noteOnTimes, 0);
     absl::c_fill(noteOffTimes, 0);
 }
diff --git a/src/sfizz/MidiState.h b/src/sfizz/MidiState.h
index f9766c81..bb42f09a 100644
--- a/src/sfizz/MidiState.h
+++ b/src/sfizz/MidiState.h
@@ -6,6 +6,7 @@
 
 #pragma once
 #include <array>
+#include <bitset>
 #include "CCMap.h"
 #include "Range.h"
 
@@ -142,6 +143,15 @@ public:
      */
     void flushEvents() noexcept;
 
+    /**
+     * @brief Check if a note is currently depressed
+     *
+     * @param noteNumber
+     * @return true
+     * @return false
+     */
+    bool isNotePressed(int noteNumber) const noexcept { return noteStates[noteNumber]; }
+
     /**
      * @brief Get the CC value for CC number
      *
@@ -191,6 +201,12 @@ private:
 
     MidiNoteArray<unsigned> noteOffTimes { {} };
 
+    /**
+     * @brief Store the note states
+     *
+     */
+    std::bitset<128> noteStates;
+
     /**
      * @brief Stores the velocity of the note ons for currently
      * depressed notes.
diff --git a/src/sfizz/Region.cpp b/src/sfizz/Region.cpp
index e066e430..e68fa48c 100644
--- a/src/sfizz/Region.cpp
+++ b/src/sfizz/Region.cpp
@@ -9,6 +9,7 @@
 #include "Macros.h"
 #include "Debug.h"
 #include "Opcode.h"
+#include "SwapAndPop.h"
 #include "StringViewHelpers.h"
 #include "ModifierHelpers.h"
 #include "modulations/ModId.h"
@@ -308,9 +309,15 @@ bool sfz::Region::parseOpcode(const Opcode& rawOpcode)
     case hash("sustain_cc"):
         sustainCC = opcode.read(Default::sustainCC);
         break;
+    case hash("sostenuto_cc"):
+        sostenutoCC = opcode.read(Default::sostenutoCC);
+        break;
     case hash("sustain_lo"):
         sustainThreshold = opcode.read(Default::sustainThreshold);
         break;
+    case hash("sostenuto_lo"):
+        sostenutoThreshold = opcode.read(Default::sostenutoThreshold);
+        break;
     case hash("sustain_sw"):
         checkSustain = opcode.read(Default::checkSustain);
         break;
@@ -1497,6 +1504,53 @@ bool sfz::Region::isSwitchedOn() const noexcept
     return keySwitched && previousKeySwitched && sequenceSwitched && pitchSwitched && bpmSwitched && aftertouchSwitched && ccSwitched.all();
 }
 
+void sfz::Region::delaySustainRelease(int noteNumber, float velocity) noexcept
+{
+    if (delayedSustainReleases.size() == delayedSustainReleases.capacity())
+        return;
+
+    delayedSustainReleases.emplace_back(noteNumber, velocity);
+}
+
+void sfz::Region::delaySostenutoRelease(int noteNumber, float velocity) noexcept
+{
+    if (delayedSostenutoReleases.size() == delayedSostenutoReleases.capacity())
+        return;
+
+    delayedSostenutoReleases.emplace_back(noteNumber, velocity);
+}
+
+void sfz::Region::removeFromSostenutoReleases(int noteNumber) noexcept
+{
+    swapAndPopFirst(delayedSostenutoReleases, [=](const std::pair<int, float>& p) {
+        return p.first == noteNumber;
+    });
+}
+
+void sfz::Region::storeSostenutoNotes() noexcept
+{
+    ASSERT(delayedSostenutoReleases.empty());
+    for (int note = keyRange.getStart(); note <= keyRange.getEnd(); ++note) {
+        if (midiState.isNotePressed(note))
+            delaySostenutoRelease(note, midiState.getNoteVelocity(note));
+    }
+}
+
+
+bool sfz::Region::isNoteSustained(int noteNumber) const noexcept
+{
+    return absl::c_find_if(delayedSustainReleases, [=](const std::pair<int, float>& p) {
+        return p.first == noteNumber;
+    }) != delayedSustainReleases.end();
+}
+
+bool sfz::Region::isNoteSostenutoed(int noteNumber) const noexcept
+{
+    return absl::c_find_if(delayedSostenutoReleases, [=](const std::pair<int, float>& p) {
+        return p.first == noteNumber;
+    }) != delayedSostenutoReleases.end();
+}
+
 bool sfz::Region::registerNoteOn(int noteNumber, float velocity, float randValue) noexcept
 {
     ASSERT(velocity >= 0.0f && velocity <= 1.0f);
@@ -1551,13 +1605,20 @@ bool sfz::Region::registerNoteOff(int noteNumber, float velocity, float randValu
         return true;
 
     if (trigger == Trigger::release) {
-        if (midiState.getCCValue(sustainCC) < sustainThreshold)
-            return true;
+        const bool sostenutoed = isNoteSostenutoed(noteNumber);
 
-        // If we reach this part, we're storing the notes to delay their release on CC up
-        // This is handled by the Synth object
+        if (sostenutoed && !sostenutoPressed) {
+            removeFromSostenutoReleases(noteNumber);
+            if (sustainPressed)
+                delaySustainRelease(noteNumber, midiState.getNoteVelocity(noteNumber));
+        }
 
-        delayedReleases.emplace_back(noteNumber, midiState.getNoteVelocity(noteNumber));
+        if (!sostenutoPressed || !sostenutoed) {
+            if (sustainPressed)
+                delaySustainRelease(noteNumber, midiState.getNoteVelocity(noteNumber));
+            else
+                return true;
+        }
     }
 
     return false;
@@ -1567,6 +1628,20 @@ bool sfz::Region::registerCC(int ccNumber, float ccValue) noexcept
 {
     ASSERT(ccValue >= 0.0f && ccValue <= 1.0f);
 
+    if (ccNumber == sustainCC)
+        sustainPressed = checkSustain && ccValue >= sustainThreshold;
+
+    if (ccNumber == sostenutoCC) {
+        const bool newState = checkSostenuto && ccValue >= sostenutoThreshold;
+        if (!sostenutoPressed && newState)
+            storeSostenutoNotes();
+
+        if (!newState && sostenutoPressed)
+            delayedSostenutoReleases.clear();
+
+        sostenutoPressed = newState;
+    }
+
     if (ccConditions.getWithDefault(ccNumber).containsWithEnd(ccValue))
         ccSwitched.set(ccNumber, true);
     else
diff --git a/src/sfizz/Region.h b/src/sfizz/Region.h
index 5cf21180..aa089908 100644
--- a/src/sfizz/Region.h
+++ b/src/sfizz/Region.h
@@ -406,7 +406,9 @@ struct Region {
     bool checkSustain { Default::checkSustain }; // sustain_sw
     bool checkSostenuto { Default::checkSostenuto }; // sostenuto_sw
     uint16_t sustainCC { Default::sustainCC }; // sustain_cc
+    uint16_t sostenutoCC { Default::sostenutoCC }; // sustain_cc
     float sustainThreshold { Default::sustainThreshold }; // sustain_cc
+    float sostenutoThreshold { Default::sostenutoThreshold }; // sustain_cc
 
     // Region logic: internal conditions
     UncheckedRange<float> aftertouchRange { Default::loChannelAftertouch, Default::hiChannelAftertouch }; // hichanaft and lochanaft
@@ -506,7 +508,16 @@ struct Region {
     RegionSet* parent { nullptr };
 
     // Started notes
-    std::vector<std::pair<int, float>> delayedReleases;
+    bool sustainPressed { false };
+    bool sostenutoPressed { false };
+    std::vector<std::pair<int, float>> delayedSustainReleases;
+    std::vector<std::pair<int, float>> delayedSostenutoReleases;
+    void delaySustainRelease(int noteNumber, float velocity) noexcept;
+    void delaySostenutoRelease(int noteNumber, float velocity) noexcept;
+    void storeSostenutoNotes() noexcept;
+    void removeFromSostenutoReleases(int noteNumber) noexcept;
+    bool isNoteSustained(int noteNumber) const noexcept;
+    bool isNoteSostenutoed(int noteNumber) const noexcept;
 
     const MidiState& midiState;
     bool keySwitched { true };
diff --git a/src/sfizz/Synth.cpp b/src/sfizz/Synth.cpp
index 879816b1..b0f6fc71 100644
--- a/src/sfizz/Synth.cpp
+++ b/src/sfizz/Synth.cpp
@@ -205,7 +205,12 @@ void Synth::Impl::buildRegion(const std::vector<Opcode>& regionOpcodes)
     }
 
     // Adapt the size of the delayed releases to avoid allocating later on
-    lastRegion->delayedReleases.reserve(lastRegion->keyRange.length());
+    if (lastRegion->trigger == Trigger::release) {
+        const auto keyLength = static_cast<unsigned>(lastRegion->keyRange.length());
+        const auto size = max(config::delayedReleaseVoices, keyLength);
+        lastRegion->delayedSustainReleases.reserve(size);
+        lastRegion->delayedSostenutoReleases.reserve(size);
+    }
 
     regions_.push_back(std::move(lastRegion));
 }
@@ -654,7 +659,8 @@ void Synth::Impl::finalizeSfzLoad()
         for (int cc = 0; cc < config::numCCs; cc++) {
             if (region->ccTriggers.contains(cc)
                 || region->ccConditions.contains(cc)
-                || (cc == region->sustainCC && region->trigger == Trigger::release))
+                || (cc == region->sustainCC && region->trigger == Trigger::release)
+                || (cc == region->sostenutoCC && region->trigger == Trigger::release))
                 ccActivationLists_[cc].push_back(region);
         }
 
@@ -1147,21 +1153,34 @@ void Synth::Impl::noteOnDispatch(int delay, int noteNumber, float velocity) noex
         region->previousKeySwitched = (*region->previousKeyswitch == noteNumber);
 }
 
-void Synth::Impl::startDelayedReleaseVoices(Region* region, int delay, SisterVoiceRingBuilder& ring) noexcept
+void Synth::Impl::startDelayedSustainReleases(Region* region, int delay, SisterVoiceRingBuilder& ring) noexcept
 {
     if (!region->rtDead && !voiceManager_.playingAttackVoice(region)) {
-        region->delayedReleases.clear();
+        region->delayedSustainReleases.clear();
         return;
     }
 
-    for (auto& note: region->delayedReleases) {
-        // FIXME: we really need to have some form of common method to find and start voices...
+    for (auto& note: region->delayedSustainReleases) {
         const TriggerEvent noteOffEvent { TriggerEventType::NoteOff, note.first, note.second };
         startVoice(region, delay, noteOffEvent, ring);
     }
-    region->delayedReleases.clear();
+
+    region->delayedSustainReleases.clear();
 }
 
+void Synth::Impl::startDelayedSostenutoReleases(Region* region, int delay, SisterVoiceRingBuilder& ring) noexcept
+{
+    if (!region->rtDead && !voiceManager_.playingAttackVoice(region)) {
+        region->delayedSostenutoReleases.clear();
+        return;
+    }
+
+    for (auto& note: region->delayedSostenutoReleases) {
+        const TriggerEvent noteOffEvent { TriggerEventType::NoteOff, note.first, note.second };
+        startVoice(region, delay, noteOffEvent, ring);
+    }
+    region->delayedSostenutoReleases.clear();
+}
 
 void Synth::cc(int delay, int ccNumber, uint8_t ccValue) noexcept
 {
@@ -1174,8 +1193,19 @@ void Synth::Impl::ccDispatch(int delay, int ccNumber, float value) noexcept
     SisterVoiceRingBuilder ring;
     const TriggerEvent triggerEvent { TriggerEventType::CC, ccNumber, value };
     for (auto& region : ccActivationLists_[ccNumber]) {
-        if (ccNumber == region->sustainCC)
-            startDelayedReleaseVoices(region, delay, ring);
+        if (region->checkSustain && ccNumber == region->sustainCC && value < region->sustainThreshold)
+            startDelayedSustainReleases(region, delay, ring);
+
+        if (region->checkSostenuto && ccNumber == region->sostenutoCC && value < region->sostenutoThreshold) {
+            if (region->sustainPressed) {
+                for (const auto& v: region->delayedSostenutoReleases)
+                    region->delaySustainRelease(v.first, v.second);
+
+                region->delayedSostenutoReleases.clear();
+            } else {
+                startDelayedSostenutoReleases(region, delay, ring);
+            }
+        }
 
         if (region->registerCC(ccNumber, value))
             startVoice(region, delay, triggerEvent, ring);
diff --git a/src/sfizz/SynthMessaging.cpp b/src/sfizz/SynthMessaging.cpp
index b4bd7e5e..3a713858 100644
--- a/src/sfizz/SynthMessaging.cpp
+++ b/src/sfizz/SynthMessaging.cpp
@@ -1042,11 +1042,21 @@ void sfz::Synth::dispatchMessage(Client& client, int delay, const char* path, co
             client.receive<'i'>(delay, path, region.sustainCC);
         } break;
 
+        MATCH("/region&/sostenuto_cc", "") {
+            GET_REGION_OR_BREAK(indices[0])
+            client.receive<'i'>(delay, path, region.sostenutoCC);
+        } break;
+
         MATCH("/region&/sustain_lo", "") {
             GET_REGION_OR_BREAK(indices[0])
             client.receive<'f'>(delay, path, region.sustainThreshold);
         } break;
 
+        MATCH("/region&/sostenuto_lo", "") {
+            GET_REGION_OR_BREAK(indices[0])
+            client.receive<'f'>(delay, path, region.sostenutoThreshold);
+        } break;
+
         MATCH("/region&/oscillator_phase", "") {
             GET_REGION_OR_BREAK(indices[0])
             client.receive<'f'>(delay, path, region.oscillatorPhase);
diff --git a/src/sfizz/SynthPrivate.h b/src/sfizz/SynthPrivate.h
index 502f548b..b40ebcc7 100644
--- a/src/sfizz/SynthPrivate.h
+++ b/src/sfizz/SynthPrivate.h
@@ -155,13 +155,22 @@ struct Synth::Impl final: public Parser::Listener {
     void startVoice(Region* region, int delay, const TriggerEvent& triggerEvent, SisterVoiceRingBuilder& ring) noexcept;
 
     /**
-     * @brief Start all delayed release voices of the region if necessary
+     * @brief Start all delayed sustain release voices of the region if necessary
      *
      * @param region
      * @param delay
      * @param ring
      */
-    void startDelayedReleaseVoices(Region* region, int delay, SisterVoiceRingBuilder& ring) noexcept;
+    void startDelayedSustainReleases(Region* region, int delay, SisterVoiceRingBuilder& ring) noexcept;
+
+    /**
+     * @brief Start all delayed sostenuto release voices of the region if necessary
+     *
+     * @param region
+     * @param delay
+     * @param ring
+     */
+    void startDelayedSostenutoReleases(Region* region, int delay, SisterVoiceRingBuilder& ring) noexcept;
 
     /**
      * @brief Finalize SFZ loading, following a successful execution of the
diff --git a/src/sfizz/Voice.cpp b/src/sfizz/Voice.cpp
index 94aba5bb..92294130 100644
--- a/src/sfizz/Voice.cpp
+++ b/src/sfizz/Voice.cpp
@@ -202,6 +202,10 @@ struct Voice::Impl
 
     State state_ { State::idle };
     bool noteIsOff_ { false };
+    enum class SustainState { Up, Sustaining };
+    SustainState sustainState_ { SustainState::Up };
+    enum class SostenutoState { Up, Sustaining, PreviouslyDown };
+    SostenutoState sostenutoState_ { SostenutoState::Up };
 
     TriggerEvent triggerEvent_;
     absl::optional<int> triggerDelay_;
@@ -459,6 +463,20 @@ bool Voice::startVoice(Region* region, int delay, const TriggerEvent& event) noe
     impl.resources_.modMatrix.initVoice(impl.id_, region->getId(), impl.initialDelay_);
     impl.saveModulationTargets(region);
 
+    if (region->checkSustain) {
+        const bool sustainPressed =
+            impl.resources_.midiState.getCCValue(region->sustainCC) >= region->sustainThreshold;
+        impl.sustainState_ =
+            sustainPressed ? Impl::SustainState::Sustaining : Impl::SustainState::Up;
+    }
+
+    if (region->checkSostenuto) {
+        const bool sostenutoPressed =
+            impl.resources_.midiState.getCCValue(region->sostenutoCC) >= region->sostenutoThreshold;
+        impl.sostenutoState_ =
+            sostenutoPressed ? Impl::SostenutoState::PreviouslyDown : Impl::SostenutoState::Up;
+    }
+
     return true;
 }
 
@@ -543,8 +561,13 @@ void Voice::registerNoteOff(int delay, int noteNumber, float velocity) noexcept
         if (impl.region_->loopMode == LoopMode::one_shot)
             return;
 
-        if (!impl.region_->checkSustain
-            || impl.resources_.midiState.getCCValue(impl.region_->sustainCC) < impl.region_->sustainThreshold)
+        const bool sustainPedalReleaseCondition = !impl.region_->checkSustain
+            || impl.sustainState_ != Impl::SustainState::Sustaining;
+
+        const bool sostenutoPedalReleaseCondition = !impl.region_->checkSostenuto
+            || impl.sostenutoState_ != Impl::SostenutoState::Sustaining;
+
+        if (sustainPedalReleaseCondition && sostenutoPedalReleaseCondition)
             release(delay);
     }
 }
@@ -559,10 +582,29 @@ void Voice::registerCC(int delay, int ccNumber, float ccValue) noexcept
     if (impl.state_ != State::playing)
         return;
 
-    if (impl.region_->checkSustain
-        && impl.noteIsOff_
-        && ccNumber == impl.region_->sustainCC
-        && ccValue < impl.region_->sustainThreshold)
+    if (impl.region_->checkSustain && (ccNumber == impl.region_->sostenutoCC)) {
+        if (ccValue < impl.region_->sostenutoThreshold) {
+            impl.sostenutoState_ = Impl::SostenutoState::Up;
+        } else if (impl.sostenutoState_ == Impl::SostenutoState::Up) {
+            impl.sostenutoState_ = Impl::SostenutoState::Sustaining;
+        }
+    }
+
+    if (impl.region_->checkSostenuto && (ccNumber == impl.region_->sustainCC)) {
+        if (ccValue < impl.region_->sustainThreshold) {
+            impl.sustainState_ = Impl::SustainState::Up;
+        } else {
+            impl.sustainState_ = Impl::SustainState::Sustaining;
+        }
+    }
+
+    const bool sustainPedalReleaseCondition = !impl.region_->checkSustain
+        || (impl.sustainState_ != Impl::SustainState::Sustaining);
+
+    const bool sostenutoPedalReleaseCondition = !impl.region_->checkSostenuto
+        || (impl.sostenutoState_ != Impl::SostenutoState::Sustaining);
+
+    if (impl.noteIsOff_ && sostenutoPedalReleaseCondition && sustainPedalReleaseCondition)
         release(delay);
 }
 
@@ -1512,6 +1554,7 @@ void Voice::reset() noexcept
     impl.count_ = 1;
     impl.floatPositionOffset_ = 0.0f;
     impl.noteIsOff_ = false;
+    impl.sostenutoState_ = Impl::SostenutoState::Up;
 
     impl.resetLoopInformation();
 
diff --git a/tests/DirectRegionT.cpp b/tests/DirectRegionT.cpp
index 75c66453..8f5bf6a6 100644
--- a/tests/DirectRegionT.cpp
+++ b/tests/DirectRegionT.cpp
@@ -37,10 +37,12 @@ TEST_CASE("[Direct Region Tests] Release and release key")
     region.parseOpcode({ "lokey", "63" });
     region.parseOpcode({ "hikey", "65" });
     region.parseOpcode({ "sample", "*sine" });
+    region.delayedSustainReleases.reserve(config::delayedReleaseVoices);
     SECTION("Release key without sustain")
     {
         region.parseOpcode({ "trigger", "release_key" });
         midiState.ccEvent(0, 64, 0.0f);
+        region.registerCC(64, 0.0f);
         REQUIRE( !region.registerNoteOn(63, 0.5f, 0.0f) );
         REQUIRE( region.registerNoteOff(63, 0.5f, 0.0f) );
     }
@@ -48,6 +50,7 @@ TEST_CASE("[Direct Region Tests] Release and release key")
     {
         region.parseOpcode({ "trigger", "release_key" });
         midiState.ccEvent(0, 64, 1.0f);
+        region.registerCC(64, 1.0f);
         REQUIRE( !region.registerCC(64, 1.0f) );
         REQUIRE( !region.registerNoteOn(63, 0.5f, 0.0f) );
         REQUIRE( region.registerNoteOff(63, 0.5f, 0.0f) );
@@ -57,6 +60,7 @@ TEST_CASE("[Direct Region Tests] Release and release key")
     {
         region.parseOpcode({ "trigger", "release" });
         midiState.ccEvent(0, 64, 0.0f);
+        region.registerCC(64, 0.0f);
         REQUIRE( !region.registerNoteOn(63, 0.5f, 0.0f) );
         REQUIRE( region.registerNoteOff(63, 0.5f, 0.0f) );
     }
@@ -65,48 +69,51 @@ TEST_CASE("[Direct Region Tests] Release and release key")
     {
         region.parseOpcode({ "trigger", "release" });
         midiState.ccEvent(0, 64, 1.0f);
+        region.registerCC(64, 1.0f);
         midiState.noteOnEvent(0, 63, 0.5f);
         REQUIRE( !region.registerNoteOn(63, 0.5f, 0.0f) );
         REQUIRE( !region.registerNoteOff(63, 0.5f, 0.0f) );
-        REQUIRE( region.delayedReleases.size() == 1 );
+        REQUIRE( region.delayedSustainReleases.size() == 1 );
         std::vector<std::pair<int, float>> expected = {
             { 63, 0.5f }
         };
-        REQUIRE( region.delayedReleases == expected );
+        REQUIRE( region.delayedSustainReleases == expected );
     }
 
     SECTION("Release with sustain and 2 notes")
     {
         region.parseOpcode({ "trigger", "release" });
         midiState.ccEvent(0, 64, 1.0f);
+        region.registerCC(64, 1.0f);
         midiState.noteOnEvent(0, 63, 0.5f);
         REQUIRE( !region.registerNoteOn(63, 0.5f, 0.0f) );
         midiState.noteOnEvent(0, 64, 0.6f);
         REQUIRE( !region.registerNoteOn(64, 0.6f, 0.0f) );
         REQUIRE( !region.registerNoteOff(63, 0.0f, 0.0f) );
         REQUIRE( !region.registerNoteOff(64, 0.2f, 0.0f) );
-        REQUIRE( region.delayedReleases.size() == 2 );
+        REQUIRE( region.delayedSustainReleases.size() == 2 );
         std::vector<std::pair<int, float>> expected = {
             { 63, 0.5f },
             { 64, 0.6f }
         };
-        REQUIRE( region.delayedReleases == expected );
+        REQUIRE( region.delayedSustainReleases == expected );
     }
 
     SECTION("Release with sustain and 2 notes but 1 outside")
     {
         region.parseOpcode({ "trigger", "release" });
         midiState.ccEvent(0, 64, 1.0f);
+        region.registerCC(64, 1.0f);
         midiState.noteOnEvent(0, 63, 0.5f);
         REQUIRE( !region.registerNoteOn(63, 0.5f, 0.0f) );
         midiState.noteOnEvent(0, 66, 0.6f);
         REQUIRE( !region.registerNoteOn(66, 0.6f, 0.0f) );
         REQUIRE( !region.registerNoteOff(63, 0.0f, 0.0f) );
         REQUIRE( !region.registerNoteOff(66, 0.2f, 0.0f) );
-        REQUIRE( region.delayedReleases.size() == 1 );
+        REQUIRE( region.delayedSustainReleases.size() == 1 );
         std::vector<std::pair<int, float>> expected = {
             { 63, 0.5f }
         };
-        REQUIRE( region.delayedReleases == expected );
+        REQUIRE( region.delayedSustainReleases == expected );
     }
 }
diff --git a/tests/RegionValuesT.cpp b/tests/RegionValuesT.cpp
index 6b5dfbf5..1feb9cf1 100644
--- a/tests/RegionValuesT.cpp
+++ b/tests/RegionValuesT.cpp
@@ -2425,6 +2425,52 @@ TEST_CASE("[Values] Sustain low")
     REQUIRE(messageList == expected);
 }
 
+TEST_CASE("[Values] Sostenuto CC")
+{
+    Synth synth;
+    std::vector<std::string> messageList;
+    Client client(&messageList);
+    client.setReceiveCallback(&simpleMessageReceiver);
+
+    synth.loadSfzString(fs::current_path() / "tests/TestFiles/value_tests.sfz", R"(
+        <region> sample=kick.wav
+        <region> sample=kick.wav sostenuto_cc=10
+        <region> sample=kick.wav sostenuto_cc=20 sostenuto_cc=-1
+    )");
+    synth.dispatchMessage(client, 0, "/region0/sostenuto_cc", "", nullptr);
+    synth.dispatchMessage(client, 0, "/region1/sostenuto_cc", "", nullptr);
+    synth.dispatchMessage(client, 0, "/region2/sostenuto_cc", "", nullptr);
+    std::vector<std::string> expected {
+        "/region0/sostenuto_cc,i : { 66 }",
+        "/region1/sostenuto_cc,i : { 10 }",
+        "/region2/sostenuto_cc,i : { 66 }",
+    };
+    REQUIRE(messageList == expected);
+}
+
+TEST_CASE("[Values] Sostenuto low")
+{
+    Synth synth;
+    std::vector<std::string> messageList;
+    Client client(&messageList);
+    client.setReceiveCallback(&simpleMessageReceiver);
+
+    synth.loadSfzString(fs::current_path() / "tests/TestFiles/value_tests.sfz", R"(
+        <region> sample=kick.wav
+        <region> sample=kick.wav sostenuto_lo=10
+        <region> sample=kick.wav sostenuto_lo=10 sostenuto_lo=-1
+    )");
+    synth.dispatchMessage(client, 0, "/region0/sostenuto_lo", "", nullptr);
+    synth.dispatchMessage(client, 0, "/region1/sostenuto_lo", "", nullptr);
+    synth.dispatchMessage(client, 0, "/region2/sostenuto_lo", "", nullptr);
+    std::vector<std::string> expected {
+        "/region0/sostenuto_lo,f : { 0.00787402 }",
+        "/region1/sostenuto_lo,f : { 0.0787402 }",
+        "/region2/sostenuto_lo,f : { -0.00787402 }",
+    };
+    REQUIRE(messageList == expected);
+}
+
 TEST_CASE("[Values] Oscillator phase")
 {
     Synth synth;
diff --git a/tests/SynthT.cpp b/tests/SynthT.cpp
index 3bf2cc64..cb97a0f7 100644
--- a/tests/SynthT.cpp
+++ b/tests/SynthT.cpp
@@ -771,8 +771,6 @@ TEST_CASE("[Synth] Release (pedal was already down)")
     REQUIRE( synth.getNumActiveVoices() == 2 );
 }
 
-
-
 TEST_CASE("[Synth] Release samples don't play unless there is another playing region that matches")
 {
     sfz::Synth synth;
@@ -793,7 +791,7 @@ TEST_CASE("[Synth] Release key (Different sustain CC)")
 {
     sfz::Synth synth;
     synth.loadSfzString(fs::current_path() / "tests/TestFiles/release.sfz", R"(
-        <global>sustain_cc=54
+        <global> sustain_cc=54
         <region> key=62 sample=*sine trigger=release_key
     )");
     synth.noteOn(0, 62, 85);
@@ -806,7 +804,7 @@ TEST_CASE("[Synth] Release (Different sustain CC)")
 {
     sfz::Synth synth;
     synth.loadSfzString(fs::current_path() / "tests/TestFiles/release.sfz", R"(
-        <global>sustain_cc=54
+        <global> sustain_cc=54
         <region> key=62 sample=*silence
         <region> key=62 sample=*sine trigger=release
     )");
@@ -818,6 +816,114 @@ TEST_CASE("[Synth] Release (Different sustain CC)")
     REQUIRE( synth.getNumActiveVoices() == 2 );
 }
 
+TEST_CASE("[Synth] Release (don't check sustain)")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path() / "tests/TestFiles/release.sfz", R"(
+        <global>sustain_cc=54 sustain_sw=off
+        <region> key=62 sample=*silence
+        <region> key=62 sample=*sine trigger=release
+    )");
+    synth.noteOn(0, 62, 85);
+    synth.cc(0, 54, 127);
+    synth.noteOff(0, 62, 85);
+    REQUIRE( synth.getNumActiveVoices() == 2 );
+}
+
+TEST_CASE("[Synth] Release key (Different sostenuto CC)")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path() / "tests/TestFiles/release.sfz", R"(
+        <global> sostenuto_cc=54
+        <region> key=62 sample=*sine trigger=release_key
+    )");
+    synth.noteOn(0, 62, 85);
+    synth.cc(0, 54, 127);
+    synth.noteOff(0, 62, 85);
+    REQUIRE( synth.getNumActiveVoices() == 1 );
+}
+
+TEST_CASE("[Synth] Release (don't check sostenuto)")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path() / "tests/TestFiles/release.sfz", R"(
+        <global> sostenuto_cc=54 sostenuto_sw=off
+        <region> key=62 sample=*silence
+        <region> key=62 sample=*sine trigger=release
+    )");
+    synth.noteOn(0, 62, 85);
+    synth.cc(0, 54, 127);
+    synth.noteOff(0, 62, 85);
+    REQUIRE( synth.getNumActiveVoices() == 2 );
+}
+
+TEST_CASE("[Synth] Release (Different sostenuto CC)")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path() / "tests/TestFiles/release.sfz", R"(
+        <global> sostenuto_cc=54
+        <region> key=62 sample=*silence
+        <region> key=62 sample=*sine trigger=release
+        <region> key=64 sample=*silence
+        <region> key=64 sample=*sine trigger=release
+    )");
+    SECTION("One note with sostenuto")
+    {
+        synth.noteOn(0, 62, 85);
+        synth.cc(1, 54, 127);
+        synth.noteOff(2, 62, 85);
+        REQUIRE( synth.getNumActiveVoices() == 1 );
+        synth.cc(3, 54, 0);
+        REQUIRE( synth.getNumActiveVoices() == 2 );
+    }
+    SECTION("Two notes, only one with sostenuto")
+    {
+        synth.noteOn(0, 62, 85);
+        synth.cc(1, 54, 127);
+        synth.noteOn(2, 64, 85);
+        synth.noteOff(3, 62, 85);
+        synth.noteOff(3, 64, 85);
+        REQUIRE( synth.getNumActiveVoices() == 3 );
+        synth.cc(4, 54, 0);
+        REQUIRE( synth.getNumActiveVoices() == 4 );
+    }
+}
+
+TEST_CASE("[Synth] Release (sustain + sostenuto)")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path() / "tests/TestFiles/release.sfz", R"(
+        <region> key=62 sample=*silence
+        <region> key=62 sample=*sine trigger=release
+        <region> key=64 sample=*silence
+        <region> key=64 sample=*sine trigger=release
+    )");
+    SECTION("Sustain up first")
+    {
+        synth.noteOn(0, 62, 85);
+        synth.cc(1, 66, 127);
+        synth.cc(1, 64, 127);
+        synth.noteOff(2, 62, 85);
+        REQUIRE( synth.getNumActiveVoices() == 1 );
+        synth.cc(3, 64, 0);
+        REQUIRE( synth.getNumActiveVoices() == 1 );
+        synth.cc(4, 66, 0);
+        REQUIRE( synth.getNumActiveVoices() == 2 );
+    }
+    SECTION("Sostenuto up first")
+    {
+        synth.noteOn(0, 62, 85);
+        synth.cc(1, 66, 127);
+        synth.cc(1, 64, 127);
+        synth.noteOff(2, 62, 85);
+        REQUIRE( synth.getNumActiveVoices() == 1 );
+        synth.cc(3, 66, 0);
+        REQUIRE( synth.getNumActiveVoices() == 1 );
+        synth.cc(4, 64, 0);
+        REQUIRE( synth.getNumActiveVoices() == 2 );
+    }
+}
+
 TEST_CASE("[Synth] Sustain threshold default")
 {
     sfz::Synth synth;
@@ -852,6 +958,108 @@ TEST_CASE("[Synth] Sustain threshold")
     REQUIRE( synth.getNumActiveVoices() == 5 );
 }
 
+TEST_CASE("[Synth] Sustain")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path() / "tests/TestFiles/sostenuto.sfz", R"(
+        <region> sample=*sine
+    )");
+
+    SECTION("1 note")
+    {
+        synth.noteOn(0, 62, 85);
+        REQUIRE( numPlayingVoices(synth) == 1 );
+        synth.cc(1, 64, 1);
+        synth.noteOff(2, 62, 85);
+        REQUIRE( numPlayingVoices(synth) == 1 );
+        synth.cc(3, 64, 0);
+        REQUIRE( numPlayingVoices(synth) == 0 );
+    }
+
+    SECTION("2 notes")
+    {
+        synth.noteOn(0, 62, 85);
+        synth.noteOn(0, 64, 85);
+        synth.cc(1, 64, 1);
+        synth.noteOff(2, 62, 85);
+        synth.noteOff(2, 64, 85);
+        REQUIRE( numPlayingVoices(synth) == 2 );
+        synth.cc(3, 64, 0);
+        REQUIRE( numPlayingVoices(synth) == 0 );
+    }
+
+    SECTION("1 note after the pedal is depressed")
+    {
+        synth.cc(0, 64, 1);
+        synth.noteOn(1, 62, 85);
+        synth.noteOff(2, 62, 85);
+        REQUIRE( numPlayingVoices(synth) == 1 );
+        synth.cc(3, 64, 0);
+        REQUIRE( numPlayingVoices(synth) == 0 );
+    }
+
+    SECTION("2 notes, 1 after the pedal is depressed")
+    {
+        synth.noteOn(0, 62, 85);
+        synth.cc(1, 64, 1);
+        synth.noteOn(2, 64, 85);
+        synth.noteOff(3, 62, 85);
+        synth.noteOff(3, 64, 85);
+        REQUIRE( numPlayingVoices(synth) == 2 );
+        synth.cc(4, 64, 0);
+        REQUIRE( numPlayingVoices(synth) == 0 );
+    }
+}
+
+TEST_CASE("[Synth] Sostenuto")
+{
+    sfz::Synth synth;
+    synth.loadSfzString(fs::current_path() / "tests/TestFiles/sostenuto.sfz", R"(
+        <region> sample=*sine
+    )");
+
+    SECTION("1 note")
+    {
+        synth.noteOn(0, 62, 85);
+        synth.cc(1, 66, 1);
+        synth.noteOff(2, 62, 85);
+        REQUIRE( numPlayingVoices(synth) == 1 );
+        synth.cc(3, 66, 0);
+        REQUIRE( numPlayingVoices(synth) == 0 );
+    }
+
+    SECTION("2 notes")
+    {
+        synth.noteOn(0, 62, 85);
+        synth.noteOn(0, 64, 85);
+        synth.cc(1, 66, 1);
+        synth.noteOff(2, 62, 85);
+        synth.noteOff(2, 64, 85);
+        REQUIRE( numPlayingVoices(synth) == 2 );
+        synth.cc(3, 66, 0);
+        REQUIRE( numPlayingVoices(synth) == 0 );
+    }
+
+    SECTION("1 note but after the pedal is depressed")
+    {
+        synth.cc(0, 66, 1);
+        synth.noteOn(1, 62, 85);
+        synth.noteOff(2, 62, 85);
+        REQUIRE( numPlayingVoices(synth) == 0 );
+    }
+
+    SECTION("2 notes, 1 after the pedal is depressed")
+    {
+        synth.noteOn(0, 62, 85);
+        synth.cc(1, 66, 1);
+        synth.noteOn(2, 64, 85);
+        synth.noteOff(3, 62, 85);
+        synth.noteOff(3, 64, 85);
+        REQUIRE( numPlayingVoices(synth) == 1 );
+        REQUIRE( getActiveVoices(synth)[0]->getTriggerEvent().number == 62 );
+    }
+}
+
 TEST_CASE("[Synth] Release (Multiple notes, release_key ignores the pedal)")
 {
     sfz::Synth synth;
@@ -903,7 +1111,7 @@ TEST_CASE("[Synth] Release (Multiple notes, release, cleared the delayed voices
     sortAll(requiredVelocities, actualVelocities);
     REQUIRE( requiredVelocities == actualVelocities );
 
-    REQUIRE( synth.getRegionView(1)->delayedReleases.empty() );
+    REQUIRE( synth.getRegionView(1)->delayedSustainReleases.empty() );
 }
 
 TEST_CASE("[Synth] Release (Multiple notes after pedal is down, release, cleared the delayed voices after)")
@@ -933,7 +1141,7 @@ TEST_CASE("[Synth] Release (Multiple notes after pedal is down, release, cleared
     sortAll(requiredVelocities, actualVelocities);
     REQUIRE( requiredVelocities == actualVelocities );
 
-    REQUIRE( synth.getRegionView(1)->delayedReleases.empty() );
+    REQUIRE( synth.getRegionView(1)->delayedSustainReleases.empty() );
 }
 
 TEST_CASE("[Synth] Release (Multiple note ons during pedal down)")
@@ -960,7 +1168,7 @@ TEST_CASE("[Synth] Release (Multiple note ons during pedal down)")
     }
     sortAll(requiredVelocities, actualVelocities);
     REQUIRE( requiredVelocities == actualVelocities );
-    REQUIRE( synth.getRegionView(1)->delayedReleases.empty() );
+    REQUIRE( synth.getRegionView(1)->delayedSustainReleases.empty() );
 }
 
 TEST_CASE("[Synth] No release sample after the main sample stopped sounding by default")
@@ -995,7 +1203,7 @@ TEST_CASE("[Synth] No release sample after the main sample stopped sounding by d
     synth.cc(0, 64, 0);
     REQUIRE( synth.getNumActiveVoices() == 0 );
 
-    REQUIRE( synth.getRegionView(1)->delayedReleases.empty() );
+    REQUIRE( synth.getRegionView(1)->delayedSustainReleases.empty() );
 }
 
 TEST_CASE("[Synth] If rt_dead is active the release sample can sound after the attack sample died")
@@ -1030,7 +1238,7 @@ TEST_CASE("[Synth] If rt_dead is active the release sample can sound after the a
     synth.cc(0, 64, 0);
     REQUIRE( synth.getNumActiveVoices() == 0 );
 
-    REQUIRE( synth.getRegionView(1)->delayedReleases.empty() );
+    REQUIRE( synth.getRegionView(1)->delayedSustainReleases.empty() );
 }
 
 TEST_CASE("[Synth] sw_default works at a global level")