Depends on the module I guess. If the OP is talking about upgrading the server from version 4 to version 5 of PHP, then this should have been done last year at the latest. PHP 4 is EOL and considered a risk to run on any system. Anyone still using version 4 and collecting credit card or sensitive information should be shot!

So I guess - what module was updated by your host, and why didn't they give more time than just 24 hours?