Host removing PHP5.3 and upgrade to MySQL 5.5 - should i be worried?

Currently running ZC version 1.5.1
Hosting company is upgrading overnight tonight.
I wasn't planning to upgrade ZC until after Christmas (Busiest time of year right now)
Will my world come crashing down tomorrow or should everything run ok?
I cant find any information on here suggesting either way

This says you should be OK:

http://www.zen-cart.com/content.php?48-what-are-the-server-requirements-to-run-zen-cart

Thanks Stevesh I didn't find that info.
Will keep fingers crossed and upgrade in the new year then.

According to that doc,

Zencart v1.5.1 will require 'some patches' to properly function when php5.3.x is removed ( I took that to mean...upgraded to php5.4.x or higher.)

I don't know of any place that actually lists all the 'some patches'

One such patch identified so far has been to modify includes/functions/html_output.php

Making the following change to lines 62-63 seems to bypass the problem and appears to have stopped triggering the PHP out-of-memory condition:```
if (defined('SID') && zen_not_null([B]constant([/B][B]'[/B]SID[B]'[/B][B])[/B])) {
$sid = [B]constant([/B][B]'[/B]SID[B]'[/B][B])[/B];

and it's broken!!!!
On to the help desk already (Terra Networks)

any other "Patches" I need to make?

Any error logs to provide and possibly help us help you?
(Logs folder myDEBUG files, most recent first.)

OK the guys at TerraNetwork have had a look and say my situation is unusual (Always me t-shirt now donned).
Apparently they have managed to log into my admin site and disable Gzip compression which has now solved the issue.
In the mean time I also added the new text into the html_output.php file as well while they were fiddling about.