There is currently only one offline version which is quite up to date and that is the version that @ChrisWard suggested.
However, this version does not use the same packageName as with AI2 (online), but → "com.email.appName" (in my case: → com.bodymindpower.appName).
Therefore, this version should not be suitable for updating existing apps that are already in the Play Store, because with AI2 (online version) the packageName is: → appinventor.ai_email.appName.