rsk wrote:
It means updating your libmysqlclient, and if switching major versions, rebuilding PHP to use the new version.
In Debian and Ubuntu your libmysqlclient is usually the same version as the mysql server, unless you installed newer mysql server from the backports.
So in general, the way to upgrade your client library is to upgrade your distribution.
OK, thanks.

hybinet wrote:
XO39 wrote:
By the way, does updating the client library is the same as updating PHP to a newer version?
rsk wrote:
It means updating your libmysqlclient, and if switching major versions, rebuilding PHP to use the new version.
Things are a bit more complicated nowadays, because PHP has been gradually switching to mysqlnd.
So in your case, upgrade + table_definition_cache seems to have done the trick. I still have difficulty understanding why ZenForo would want to modify table definitions in the middle of executing prepared statements, but hey, PHP CMS's tend to do weird things.
I'm not sure why, but they said they approach database access in a different way, and they totally depends on Zend Framework.