PHP upgrade... issues???

I've just got this mail from my host... ============= Dear customer, This email is sent to inform you that we'll upgrade the PHP version on your server to the latest stable version 4.3.8 within the next hour. ============= Are there any issues that I need to panic about...? I'm off to google now, but am just having a panic attack, and hope that I can sit back knowing that my PHP pages will still work... Cheers... Tris... ********************************************************************* The information contained in this e-mail message is intended only for the personal and confidential use of the recipient(s) named above. If the reader of this message is not the intended recipient or an agent responsible for delivering it to the intended recipient, you are hereby notified that you have received this document in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail, and delete the original message. ***********************************************************************