In reply to René Hermenau.

It is a misconception that this is somehow the hosters fault, when in reality the hosters probably need to put effort into supporting such an old enviroment that literaly you can not achieve now. Go and try to find a copy of 5.2 you can install by yourself. I have tried and it is mission impossible.

@Rarst pointed correctly to how WordPress itself is the cause for people running old versions https://www.rarst.net/wordpress/technical-responsibility/ by hiding information and choice from the wordpress users. No one knows if users prefer to stay on that old versions, as they are never presented with the choice. For hosters it is probably a nightmare to support them, but they have to because of wordpress.

It is not like this move is even meaningful unless BP will be refactored to use 5.3 idioms over the current 5.2. Without refactoring all you will get is two different pieces of code that a developer needs to have different mental approach in order to read and understand them, and this is not a good software development practice.