[dazzer]

Seems to me like an obsolescence strategy.

By declaring right out that it is no longer going to be supported, people will be encouraged to write for the newer databases. Eventually when the standard MySQL version moves up, it won't be stuck in 4.1. Plugins authors will also appreciate that they have been given enough heads-up to update their plugins.

This will also give people time to upgrade their databases if they're managing their own.