The message reads as follows:

Update your templates

Your templates include links to files hosted on Google Page Creator, a service that is soon migrating to Google Sites. Do you want Blogger to update those links now? Learn more

There is a ‘Update and review‘ link at the bottom of the message. Once you click it the new domain,’bloggerhosting.appspot.com’ would ask you to allow permissions to access your account. Just approve it.

Once done, you will be redirected to a page that will show all your blogs and check which one’s have references to googlepages (in their template.)

If any of your blog has a reference to googlepages in it, just click on the ‘Update References >>‘ link. It will now ask you to download (and backup) your template.

After clicking on ‘Next‘, all your references (like the scripts or css files or images) will be automatically uploaded to bloggerhosting.appspot.com. For eg. my script, that was previously hosted on http://myfreehouse2.googlepages.com/lightbox.js would now be moved to http://bloggerhosting.appspot.com/serve/myfreehouse2.googlepages.com/lightbox.js

Now all you need to do is click the ‘Update‘ button at the bottom, and your template will be modified with all the new links. Pretty neat!

So don’t wait much, as it seems the Google will now hurry up the closing of GP, and you wouldn’t want to lose any of your data, eh?