diff --git a/libs/ardour/ardour/vst3_plugin.h b/libs/ardour/ardour/vst3_plugin.h
index 364950076b..7467752f8a 100644
--- a/libs/ardour/ardour/vst3_plugin.h
+++ b/libs/ardour/ardour/vst3_plugin.h
@@ -29,6 +29,7 @@
 
 namespace ARDOUR {
 class VST3PluginModule;
+class AutomationList;
 }
 
 #if defined(__clang__)
@@ -113,6 +114,9 @@ public:
 	std::string print_parameter (Vst::ParamID, Vst::ParamValue) const;
 	bool        set_program (int p, int32 sample_off);
 
+	bool subscribe_to_automation_changes () const;
+	void automation_state_changed (uint32_t, ARDOUR::AutoState, boost::weak_ptr<ARDOUR::AutomationList>);
+
 	ARDOUR::Plugin::IOPortDescription describe_io_port (ARDOUR::DataType dt, bool input, uint32_t id) const;
 
 	uint32_t n_audio_inputs () const;
@@ -154,6 +158,11 @@ public:
 
 	void process (float** ins, float** outs, uint32_t n_samples);
 
+	/* PSL Extension */
+	Vst::IEditController* conroller () const { return _controller; }
+	bool add_slave (Vst::IEditController*, bool);
+	bool remove_slave (Vst::IEditController*);
+
 private:
 	/* prevent copy construction */
 	VST3PI (const VST3PI&);
@@ -287,6 +296,8 @@ public:
 	IOPortDescription describe_io_port (DataType dt, bool input, uint32_t id) const;
 	PluginOutputConfiguration possible_output () const;
 
+	void set_automation_control (uint32_t, boost::shared_ptr<ARDOUR::AutomationControl>);
+
 	std::string state_node_name () const { return "vst3"; }
 
 	void add_state (XMLNode*) const;
@@ -303,6 +314,9 @@ public:
 
 	void set_owner (ARDOUR::SessionObject* o);
 
+	void add_slave (boost::shared_ptr<Plugin>, bool);
+	void remove_slave (boost::shared_ptr<Plugin>);
+
 	int connect_and_run (BufferSet&  bufs,
 	                     samplepos_t start, samplepos_t end, double speed,
 	                     ChanMapping const& in, ChanMapping const& out,
diff --git a/libs/ardour/vst3_host.cc b/libs/ardour/vst3_host.cc
index 31f93cbe46..d4c2eea283 100644
--- a/libs/ardour/vst3_host.cc
+++ b/libs/ardour/vst3_host.cc
@@ -60,6 +60,16 @@ DEF_CLASS_IID (Vst::IUnitData)
 DEF_CLASS_IID (Vst::IUnitInfo)
 DEF_CLASS_IID (Vst::ChannelContext::IInfoListener)
 
+DEF_CLASS_IID (Presonus::IContextInfoProvider)
+DEF_CLASS_IID (Presonus::IContextInfoProvider2)
+DEF_CLASS_IID (Presonus::IContextInfoProvider3)
+DEF_CLASS_IID (Presonus::IContextInfoHandler)
+DEF_CLASS_IID (Presonus::IContextInfoHandler2)
+DEF_CLASS_IID (Presonus::IEditControllerExtra)
+DEF_CLASS_IID (Presonus::ISlaveControllerHandler)
+DEF_CLASS_IID (Presonus::IPlugInViewEmbedding)
+DEF_CLASS_IID (Presonus::IPlugInViewScaling)
+
 #if SMTG_OS_LINUX
 DEF_CLASS_IID (Linux::IRunLoop);
 #endif
diff --git a/libs/ardour/vst3_plugin.cc b/libs/ardour/vst3_plugin.cc
index 8f27340ff1..19a8bf0ca8 100644
--- a/libs/ardour/vst3_plugin.cc
+++ b/libs/ardour/vst3_plugin.cc
@@ -183,6 +183,15 @@ VST3Plugin::designated_bypass_port ()
 	return _plug->designated_bypass_port ();
 }
 
+void
+VST3Plugin::set_automation_control (uint32_t port, boost::shared_ptr<ARDOUR::AutomationControl> ac)
+{
+	if (!ac->alist () || !_plug->subscribe_to_automation_changes ()) {
+		return;
+	}
+	ac->alist()->automation_state_changed.connect_same_thread (_connections, boost::bind (&VST3PI::automation_state_changed, _plug, port, _1, boost::weak_ptr<AutomationList> (ac->alist ())));
+}
+
 std::set<Evoral::Parameter>
 VST3Plugin::automatable () const
 {
@@ -543,6 +552,24 @@ VST3Plugin::configure_io (ChanCount in, ChanCount out)
 	return Plugin::configure_io (in, out);
 }
 
+void
+VST3Plugin::add_slave (boost::shared_ptr<Plugin> p, bool rt)
+{
+	boost::shared_ptr<VST3Plugin> vst = boost::dynamic_pointer_cast<VST3Plugin> (p);
+	if (vst) {
+		_plug->add_slave (vst->_plug->conroller (), rt);
+	}
+}
+
+void
+VST3Plugin::remove_slave (boost::shared_ptr<Plugin> p)
+{
+	boost::shared_ptr<VST3Plugin> vst = boost::dynamic_pointer_cast<VST3Plugin> (p);
+	if (vst) {
+		_plug->remove_slave (vst->_plug->conroller ());
+	}
+}
+
 int
 VST3Plugin::connect_and_run (BufferSet&  bufs,
                              samplepos_t start, samplepos_t end, double speed,
@@ -1564,6 +1591,12 @@ VST3PI::get_parameter_descriptor (uint32_t port, ParameterDescriptor& desc) cons
 	} else if (p.unit == "Hz") {
 		desc.unit = ARDOUR::ParameterDescriptor::HZ;
 	}
+
+	FUnknownPtr<Presonus::IEditControllerExtra> extra_ctrl (_controller);
+	if (extra_ctrl) {
+		int32 flags = extra_ctrl->getParamExtraFlags (id);
+		desc.inline_ctrl = (flags & Presonus::kParamFlagMicroEdit) ? true : false;
+	}
 }
 
 std::string
@@ -2325,6 +2358,72 @@ VST3PI::setup_info_listener ()
 	stripable_property_changed (PropertyChange ());
 }
 
+/* ****************************************************************************
+ * PSL Extensions
+ */
+
+bool
+VST3PI::add_slave (Vst::IEditController* c, bool rt)
+{
+	FUnknownPtr<Presonus::ISlaveControllerHandler> slave_ctrl (_controller);
+	if (slave_ctrl) {
+		return slave_ctrl->addSlave (c, rt ? Presonus::kSlaveModeLowLatencyClone : Presonus::kSlaveModeNormal) == kResultOk;
+	}
+	return false;
+}
+
+bool
+VST3PI::remove_slave (Vst::IEditController* c)
+{
+	FUnknownPtr<Presonus::ISlaveControllerHandler> slave_ctrl (_controller);
+	if (slave_ctrl) {
+		return slave_ctrl->removeSlave (c) == kResultOk;
+	}
+	return false;
+}
+
+bool
+VST3PI::subscribe_to_automation_changes () const
+{
+	FUnknownPtr<Presonus::IEditControllerExtra> extra_ctrl (_controller);
+	return 0 != extra_ctrl ? true : false;
+}
+
+void
+VST3PI::automation_state_changed (uint32_t port, AutoState s, boost::weak_ptr <AutomationList> wal)
+{
+	Vst::ParamID id (index_to_id (port));
+	boost::shared_ptr<AutomationList> al = wal.lock ();
+	FUnknownPtr<Presonus::IEditControllerExtra> extra_ctrl (_controller);
+	assert (extra_ctrl);
+
+	Presonus::AutomationMode am;
+	switch (s) {
+		case ARDOUR::Off:
+			if (!al || al->empty ()) {
+				am = Presonus::kAutomationNone;
+			} else {
+				am = Presonus::kAutomationOff;
+			}
+			break;
+		case Write:
+				am = Presonus::kAutomationWrite;
+			break;
+		case Touch:
+				am = Presonus::kAutomationTouch;
+			break;
+		case Play:
+				am = Presonus::kAutomationRead;
+			break;
+		case Latch:
+				am = Presonus::kAutomationLatch;
+			break;
+		default:
+			assert (0);
+	}
+	extra_ctrl->setParamAutomationMode (id, am);
+}
+
 /* ****************************************************************************
  * GUI
  */