Be careful, the was a point in the 5.x releases that broke some backwards compatibility that had to do with some older defaults using one of the Latin charsets instead of utf-8. This may or may not affect the forum DB as I know you needed to support Japanese and Chinese characters from the start. I would try the upgrade on a test server with a DB copy to see if it breaks anything.
Be careful, the was a point in the 5.x releases that broke some backwards compatibility that had to do with some older defaults using one of the Latin charsets instead of utf-8. This may or may not affect the forum DB as I know you needed to support Japanese and Chinese characters from the start. I would try the upgrade on a test server with a DB copy to see if it breaks anything.
Be careful, the was a point in the 5.x releases that broke some backwards compatibility that had to do with some older defaults using one of the Latin charsets instead of utf-8. This may or may not affect the forum DB as I know you needed to support Japanese and Chinese characters from the start. I would try the upgrade on a test server with a DB copy to see if it breaks anything.
A little update: we succeeded in converting some of the problematic tables into utf8. The script written by our programmer still requires some a few adjustments, but I'm quite positive that a conversion is within the realms of possibility.
I believe they were an issue within the 5.x releases. That said if the the forum is already at 5.5 then it doesn't matter as I know 5.5 was incompatible with those issues. They were either not present in the DB at all or must have been fixed a while back. My guess is they weren't an issue as those charsets would not have supported Japanese or Chinese characters anyway.