diff --git a/libs/ardour/ardour/vst3_host.h b/libs/ardour/ardour/vst3_host.h
index 9055b6ed67..4c27fae3cf 100644
--- a/libs/ardour/ardour/vst3_host.h
+++ b/libs/ardour/ardour/vst3_host.h
@@ -298,7 +298,7 @@ public:
 	tresult PLUGIN_API createInstance (TUID cid, TUID _iid, void** obj) SMTG_OVERRIDE;
 
 protected:
-	std::shared_ptr<PlugInterfaceSupport> _plug_interface_support;
+	std::unique_ptr<PlugInterfaceSupport> _plug_interface_support;
 };
 
 class LIBARDOUR_LOCAL Vst3ParamValueQueue : public Vst::IParamValueQueue
diff --git a/libs/ardour/vst3_host.cc b/libs/ardour/vst3_host.cc
index d6a79cab5c..748832e241 100644
--- a/libs/ardour/vst3_host.cc
+++ b/libs/ardour/vst3_host.cc
@@ -20,10 +20,6 @@
 #include <algorithm>
 #include <ctype.h>
 
-#if (__cplusplus >= 201103L)
-#include <boost/make_unique.hpp>
-#endif
-
 #include "ardour/vst3_host.h"
 
 #include "pbd/atomic.h"
@@ -461,11 +457,7 @@ PlugInterfaceSupport::addPlugInterfaceSupported (const TUID id)
 
 HostApplication::HostApplication ()
 {
-#if (__cplusplus >= 201103L)
-	_plug_interface_support = boost::make_unique<PlugInterfaceSupport> ();
-#else
 	_plug_interface_support.reset (new PlugInterfaceSupport);
-#endif
 }
 
 tresult