https://www.techdirt.com/articles/20191015/09262643195/after-all-that-sony-unceremoniously-rolls-out-ps4-remote-play-to-all-android-devices.shtml

Remote play capability for the Playstation 4 has been something of a twisted, never ending saga. One of the most useful features of the gaming console, Sony has jealously guarded the ability to play its flagship console remotely on all kinds of devices. Originally, the only way you could connect to your PS4 was if you bought a Playstation Vita, a product all but abandoned at this point, or a Sony Xperia Android phone, a line of products the public almost universally ignored. When tinkerers on the internet went about making their own remote play apps that would work with Android phones and PCs, Sony worked tirelessly to update the console firmware to break those homebrew apps. Then Sony came out with its own PC remote play app. Subsequently, some months ago, Sony released remote play functionality for iOS devices only. The explanation at the time was that Sony was likely still trying to push Xperia phones, despite the complete lack of traction.

And now, unceremoniously via yet another firmware update, Sony has given up the game and enabled remote play for all Android devices.