(11 Mar 2015, 9:10 pm)aureolin wrote Same as Windows Phones or the iPhone to an extent. Android is the OS, and an app will be built to be supported on certain versions of the OS, with backwards compatibility usually included.

Android OS versions are typically known by their release name, rather than version number. Ideally you want something running Android Lollipop, with it being the latest version.

It's worth having a look at the Xperia Z3 (or wait for the Z4) which is Sony's flagship. There's also the HTC One M9, which is HTC's flagship. Both comparable to the Galaxy S5 and S6 spec wise.