Hi Edith,

I'd just like to backup Wilts comments. I'm also running MySQL 5.5.24 and haven't seen any problems with core code (or any modules I've tried).

Having said that, please be aware that most (if not all) MySQL upgrades have been backwards compatible. This is not true of PHP, which is also in version 5.x. (and I'm sure many people get these confused). You'll find that most people suffering compatibility issues are a result of the PHP updates rather than the MySQL upgrades.

Having said that, why are you asking? Are you planning an upgrade or a new installation? Perhaps if you could tell us about your current setup we will be in a better position to offer more definitive advice.
If you are planning a new install then needless to say, you should start out with the latest codebase available, keeping in mind that *you* have no control over which versions of MySQL or PHP is installed on any given server.

Cheers
Rod.