A few weeks ago Google Cloud Platform released an update for PHP on App Engine that enabled PHP 5.5 on App Engine. It was all very exciting, and there was a forum post about it any everything. At the bottom though there is a little note:
After 16th April, 2015 we will begin automatically migrating all applications to the php55 runtime.
You may have also seen emails from “Google App Engine” reminding you of this. In those notices it has been changed to:
in approximately 2 weeks we will begin automatically migrating your application over to use the PHP 5.5
If you need an extension on PHP 5.4 you can fill out a form to request one.
So this change is coming, and this post is yet another heads up to remind people.