Bug 570790: Due to a broken pyPI package of jsbridge the extension wasn’t working properly on all platforms. At least on Windows the files which have been accidentally added to the tar.gz file, caused an error when loading files from the components and chrome folder of the extension. We have removed all those instances to make sure the extension will work again.
Bug 568839: Installing binary extensions with Mozmill was broken in version 2.4.2. All files which have been extracted from the XPI were handled as ASCII files. With this fix Mozmill is now able to install any version of extensions successfully.
If you still notice any other problems please get in contact with us.