diff --git a/aegisub/Makefile.am b/aegisub/Makefile.am
index c88ac34ea..0514557b9 100644
--- a/aegisub/Makefile.am
+++ b/aegisub/Makefile.am
@@ -39,6 +39,7 @@ aegisub_SOURCES = \
 	auto4_lua.cpp \
 	auto4_lua_assfile.cpp \
 	auto4_lua_dialog.cpp \
+	auto4_auto3.cpp \
 	avisynth_wrap.cpp \
 	base_grid.cpp \
 	colorspace.cpp \
diff --git a/aegisub/changelog.txt b/aegisub/changelog.txt
index 7e8bf7eb6..164faf63d 100644
--- a/aegisub/changelog.txt
+++ b/aegisub/changelog.txt
@@ -8,6 +8,7 @@ Please visit http://aegisub.net to download latest version
   o Automation 4 Lua uses Lua 5.1 instead of 5.0, meaning some new language features:
   o It is now possible to write macros that manipulate subtitles directly
   o Scripts have full access to the entire subtitle file, not just the "Events" section
+  o Also has a compatibility Automation 3 engine, so old scripts should continue working with little or no changes
 - Visual Typesetting functionality implemented, which should make typesetting much easier and faster. It supports: (AMZ)
   o Dragging;
   o Rotation on Z axis;