diff --git a/aegisub/packages/win_installer/aegisub2-upgrade.iss b/aegisub/packages/win_installer/aegisub2-upgrade.iss
index 3e6dacf07652b2f34270037e70571a22ea49a4ac..bf2bdc371703f17ee3abb8c0aa8eccdbd3d68d08 100644
--- a/aegisub/packages/win_installer/aegisub2-upgrade.iss
+++ b/aegisub/packages/win_installer/aegisub2-upgrade.iss
@@ -74,10 +74,12 @@ begin
   try
     if RegQueryStringValue(HKLM, 'SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{24BC8B57-716C-444F-B46B-A3349B9164C5}_is1', 'DisplayVersion', OldVersionString) and
        RegQueryStringValue(HKLM, 'SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{24BC8B57-716C-444F-B46B-A3349B9164C5}_is1', 'InstallLocation', OldVersionDir) and
-       (OldVersionString = '2.1.7') and
-       FileSize(OldVersionDir + '\aegisub32.exe', OldExeSize) and
-       (OldExeSize = 5668864) and
-       (GetMD5OfFile(OldVersionDir + '\aegisub32.exe') = 'c5e6c3e6511f4c293a12c980d8c4ca6e') then
+       (
+        ((OldVersionString = '2.1.7') and FileSize(OldVersionDir + '\aegisub32.exe', OldExeSize) and (OldExeSize = 5668864) and
+         (GetMD5OfFile(OldVersionDir + '\aegisub32.exe') = 'c5e6c3e6511f4c293a12c980d8c4ca6e')) or
+        ((OldVersionString = '2.1.8') and FileSize(OldVersionDir + '\aegisub32.exe', OldExeSize) and (OldExeSize = 5595648) and
+         (GetMD5OfFile(OldVersionDir + '\aegisub32.exe') = 'ed67349f7dace0444fd5edcab5039737'))
+      ) then
     begin
       Result := True;
     end;
@@ -102,3 +104,4 @@ begin
 end;
 
 
+