Here's a summary of known 4.21 upgrade issues that are currently being reviewed.
- dirify function changed (existing dashes no longer removed in 4.2)
- Discussed on ProNet. (Subject: [ProNet] 4.2 upgrade messed up)
- http://bugs.movabletype.org/default.asp?79377
- http://code.sixapart.com/trac/movabletype/changeset/2086
Resolved by release of the EntrySetBasename Plugin
index templates set to not rebuild with indexes in pre-4.2 are mapped to "static" instead of "manually" upon upgrade
- Elise on ProNet. (Subject: [ProNet] 4.2 upgrade messed up)
- http://bugs.movabletype.org/default.asp?81689 Fixed in Development
upgrading blog using the Universal template set causes index template ids to be lost
ID conflict in Community Forum template set config
- http://bugs.movabletype.org/default.asp?81318 Fixed in Development
If I have missed any, please Submit a Bug and then place a link here in the comments.
Reported on Movable Type 4.2

I posted a few issues I'd run into that weren't MT core related over on http://www.movabletype4.eu/movabletype/gotchas-with-mt-42-upgrade.html
I also opened a couple of bugs:
Not sure if this is what you're looking for, but it's a pitfall: If you go the route of deleting your cgi-bin and mt-static directories by way of doing a fresh install per the advice in the upgrade instructions, don't forget to backup your uploaded content in the mt-static directory like the userpics,assets-c, uploads and themes directories.
That content in the mt-static directory is one thing that gets me every time. I really wish that it was elsewhere, because even though I rarely delete it, and almost always have it, I generally forget to update it until I've been reminded that it's not working as it did!
The post title indicates these are MT 4.21 issues, implying that #2 is an issue on 4.21. However, it's also marked s fixed, but there's no newer version than 4.21.
If it's fixed, should I re-download 4.21 to get the fix? How can I tell if my version of 4.21 has the fix?
I've changed the text to "Fixed in Development". The fix is available if you download the MTOS source code using Subversion and will be available in the next version.
For now if you are aware of issue #2 above, you can easily edit each index template that was previously set to "not rebuild with indexes".
Ah, that's a lot clearer, thanks.
Ah, that's a lot clearer, thanks.
I've changed the text to "Fixed in Development". The fix is available if you download the MTOS source code using Subversion and will be available in the next version.
For now if you are aware of issue #2 above, you can easily edit each index template that was previously set to "not rebuild with indexes".
Also, in Michele's bug #81665 (No warning of missing perl modules on upgrade), can anyone elaborate on what other modules may be required and what the possible issues are?
ImageMagick is required for image manipulation.
View your MT-Check cgi script to test:
Oh, if that's it I'm good then. I know that I've got ImageMagick.
Oh, if that's it I'm good then. I know that I've got ImageMagick.
ImageMagick is required for image manipulation.
View your MT-Check cgi script to test:
All of the initial issues listed here have been fixed in development.
The dirify issue has been addressed with the EntrySetBasename Plugin