No reason to panic, but it might be good to know that the XPe SP1 lifecycle support ends in April as Lynda Allen reminds in the XPe product group BLOG.
This means that no patches or updates will be available for this specific version any more.
Do not get it wrong, SP2 and FP 2007 support is not touched in any way by this termination!
So, what to do if You have SP1 images in the field?
Well, if everything is up and running there is no direct need to worry at all.
Find out if there is an urgent requirement for updating your devices e.g. because security flaws need to be fixed or functionality bugs in the OS removed. If not, leave them as they are.
If the systems need to be maintained, it would be a good approach to think about upgrading to SP2 or better FP2007.
Here a new tool, the Image Differencinging engine (currently in CTP) will be available soon that allows e.g. an in place upgrade from SP1 to SP2, FP 2007 or similar.
But deploying a new and improved complete image, of course, could be a very reasonable way to enhance the value of your in-field devices, as well.