Did you convert the data in your database from whatever charset it was using before to UTF-8? I think you need to manually do that during the pre-1.1.0-to-1.1.0 upgrade, though I can't find documentation on that right now...

Thanks for the response.

I tried that and just tried again (with a subset of the tables, like the table that contains the note text, using phpmyadmin.

Any existing text was changed to mojibake. Text that I added manually in phpmyadmin showed up fine.

When viewing the text in phpmyadmin, it always shows up garbled, however was always displayed correctly in 1.0.3. The collation of the database is latin1_swedish_ci.

Ok, so you have Japanese characters in some charset shoved into fields of latin1_swedish_ci collation. You will have to figure out how to correct this so that you have correct utf8 characters in fields of a utf8 collation. Then Mantis >= 1.1 will work correctly, and also phpMyAdmin will show the data correctly. It has been a few years since I last had to do such a conversion so I'm not sure what the best way is anymore.

Thanks for the information.

Is there an explanation as to why it broke?

paull, probably you have EUC-JP encoded Japanese stored as a latin1_swedish_ci collation. Convert that into UTF-8 and it should work.

Mantis dropped support for outdated Japanese encodings which is why it appears broken.

As mentioned by nurikabe

Convert that into UTF-8 and it should work

We are resolving this issue as "no change required", because it was reported against an old version of MantisBT which is no longer supported.

We recommend that you upgrade to the latest stable version [1]; if after doing so the problem still exists, do not hesitate to reopen the issue.

[1] http://www.mantisbt.org/download.php