In addition to the problem of old versions and lack of updates: new versions can cause problems as well. The claimed utility of PAAS is in part it doesn’t requi

In addition to the problem of old versions and lack of updates: new versions can cause problems as well. The claimed utility of PAAS is in part it doesn’t require you to upgrade software since they handle that. The problem is of course that sometimes new versions either have new bugs that break your software or may have some incompatible change that breaks your software. So if you do have a working version on a PAAS, they might potentially break it. With your own environment you can test your software with new versions before upgrading. Ideally a PAAS should provide an automated framework to run any tests you have to see whether to run you in an upgraded environment, otherwise run you on a legacy environment until you are ready to switch. They’d then need to give you access to test in the new environment separately. It isn’t clear how many different legacy environments PAAS vendors would want to keep running.