Albrecht Baur via Pharo-dev <pharo-dev@lists.pharo.org> wrote: I started trying to do the same migration process for ... http://www.smalltalkhub.com/#!/~Pier/Pier3 ... but I failed on errors loading older mcz files: "instance of ByteString did not understand #peek" on: MCMczReader >> contentsForMember: (ZnInvalidUTF8: Illegal leading byte for utf-8 encoding) That needs a bugfix, old mczs might not be utf8. You can probably retry with latin1 or macroman. Beware of issues like https://lists.gforge.inria.fr/pipermail/pharo-project/2009-May/008990.html You might find WideString there, different encodings, or a dropped leading character, and code where the method contents are changed but the timestamp didn’t and the other way around Stephan