Basicly what happens is as follows:
Security center checks the installed version of the vps with the one on the Alwil server.
If the version on the server is newer than the one installed it will report "out of date".
As you know, Alwil is "spreading" the updates to reduce server load.
So if there is nothing wrong with the system or installed applications and you get this message, invoke a manual update to get the latest vps and the message will disapear.
If you have already the latest vps and everything else seems to be alright, and you still get this message... Than there is something wrong with your system/installed application(s).