Kaj Arno writes that MySQL is dropping support for 3.23 and 4.0. Luckly I just finished our slow and painful upgrade from 3.23 to 4.1. Unfortunately, it looks like we should probably have gone straight to 5.0, because he mentioned they’re discussing dropping 4.1 support too 🙁
From what I’m reading in the docs, the upgrade from 4.1 to 5.0 should be much less painful. Most of our issues were related to huge differences between the older and newer versions of the connector/J JDBC driver, not the database server. Now that we’re on the latest driver I think the hard part is over.
Anyways, at this point we’ve almost entirely migrated to postgres anyways for our in-house software. Only a few old apps still use MySQL these days.