diff --git a/src/avisynth_wrap.cpp b/src/avisynth_wrap.cpp
index bbbcc0a3a..fd2246f77 100644
--- a/src/avisynth_wrap.cpp
+++ b/src/avisynth_wrap.cpp
@@ -63,11 +63,7 @@ AviSynthWrapper::AviSynthWrapper() {
 		if (!CreateScriptEnv)
 			throw AvisynthError("Failed to get address of CreateScriptEnv from avisynth.dll");
 
-		// Require Avisynth 2.5.6+?
-		if (OPT_GET("Provider/Avisynth/Allow Ancient")->GetBool())
-			env = CreateScriptEnv(AVISYNTH_INTERFACE_VERSION-1);
-		else
-			env = CreateScriptEnv(AVISYNTH_INTERFACE_VERSION);
+		env = CreateScriptEnv(AVISYNTH_INTERFACE_VERSION);
 
 		if (!env)
 			throw AvisynthError("Failed to create a new avisynth script environment. Avisynth is too old?");
diff --git a/src/libresrc/default_config.json b/src/libresrc/default_config.json
index 318f8d3ee..f83002436 100644
--- a/src/libresrc/default_config.json
+++ b/src/libresrc/default_config.json
@@ -335,8 +335,7 @@
 			}
 		},
 		"Avisynth" : {
-			"Allow Ancient" : false,
-			"Memory Max" : 64
+			"Memory Max" : 128
 		},
 		"FFmpegSource" : {
 			"Cache" : {
diff --git a/src/libresrc/osx/default_config.json b/src/libresrc/osx/default_config.json
index 59f2ed05f..66cecd520 100644
--- a/src/libresrc/osx/default_config.json
+++ b/src/libresrc/osx/default_config.json
@@ -335,8 +335,7 @@
 			}
 		},
 		"Avisynth" : {
-			"Allow Ancient" : false,
-			"Memory Max" : 64
+			"Memory Max" : 128
 		},
 		"FFmpegSource" : {
 			"Cache" : {
diff --git a/src/preferences.cpp b/src/preferences.cpp
index f6320dd75..38f1ac285 100644
--- a/src/preferences.cpp
+++ b/src/preferences.cpp
@@ -436,8 +436,6 @@ void Advanced_Video(wxTreebook *book, Preferences *parent) {
 
 #ifdef WITH_AVISYNTH
 	auto avisynth = p->PageSizer("Avisynth");
-	p->OptionAdd(avisynth, _("Allow pre-2.56a Avisynth"), "Provider/Avisynth/Allow Ancient");
-	p->CellSkip(avisynth);
 	p->OptionAdd(avisynth, _("Avisynth memory limit"), "Provider/Avisynth/Memory Max");
 #endif
 
diff --git a/src/project.cpp b/src/project.cpp
index e01dd3749..6bd79abf4 100644
--- a/src/project.cpp
+++ b/src/project.cpp
@@ -53,7 +53,6 @@ Project::Project(agi::Context *c) : context(c) {
 	OPT_SUB("Audio/Cache/Type", &Project::ReloadAudio, this);
 	OPT_SUB("Audio/Provider", &Project::ReloadAudio, this);
 	OPT_SUB("Provider/Audio/FFmpegSource/Decode Error Handling", &Project::ReloadAudio, this);
-	OPT_SUB("Provider/Avisynth/Allow Ancient", &Project::ReloadVideo, this);
 	OPT_SUB("Provider/Avisynth/Memory Max", &Project::ReloadVideo, this);
 	OPT_SUB("Provider/Video/FFmpegSource/Decoding Threads", &Project::ReloadVideo, this);
 	OPT_SUB("Provider/Video/FFmpegSource/Unsafe Seeking", &Project::ReloadVideo, this);