A day or so ago Apple released Safari 4.0.1 and bumped the version number in the process. Safari 4.0 was 5530.17, while Safari 4.0.1 is 5530.18. After installing the update, MiddleClickClose was still loading, even with the minor version mismatch. I don’t know if Safari only looks at the first part of the number when specified in an Info.plist for MaxBundleVersion, but just to be on the safe side, I bumped it to 5530.18 and have re-released it. If it’s working fine for you, don’t bother getting this version. That’s the only change I made.