At this time, on shared/reseller servers, we are not upgrading to 5.3.1.
This is only allowed on VPS/Dedicated servers. Before offering this to a VPS/Dedicated owner, we warn you of compatibility issues with scripts and we will need to verify you understand the changes PHP 5.3.1 will bring to your server before compiling.
So far, many users that have upgraded to 5.3 have ended up reverting to 5.2.
