I was looking in the shared hosting section and I saw that a lot of hosts advertise PHP 5.2.

I will be running joomla, oscommerce, zen cart, just the newest versions as of today and I have good experience with test running them on Xampp PHP 5.3.

If I get a host with PHP 5.2 and the host decides to upgrade one day to PHP 5.3 is that going to affect me and mess up my day?

thanks