Hello i have question how can i install legal apps which is no longer available for windows mobile 8.1 the apps is still exist in windows store just i dont have option to install
Just because an app is in the store does not mean it is for all devices. Always look at the system requirements for the app. Don't know where you get the idea apps are delisted.
They are either in the store or not. Your device either meets the hardware requirements or not.
Realistically, the only thing you can do, if it is indeed still possible, is to use the WDRT to go back to Windows Phone 8.1, like you did before, and then stay on that. Do not upgrade to W10M.
I've had decent luck upgrading to W10M on my 830 still retaining apps supposedly not obtainable on 10, they all worked perfectly fine afterwards too. Found it is if a hard reset is done whilst running W10M that they will vanish or become unusable requiring one to go through the motions again to get them back... today though I'm finding out "some of those apps" are now starting to vanish so it is just a matter of time before it becomes no longer doable.
I don't understand why MS remove apps from the Store anyway. It makes sense just to leave them there working. It doesn't harm them doing that. It only harms them when they remove apps that people still use and MS doesn't give people a way to get those apps back. That's shortsighted.
Totally agree but it seems to be Microsoft's way... the thing is, in my experiences anyway, they weren't removing some of these apps but rather delisting the phone of sorts as being ineligible to D/L due to the OS its running.
If I can use WDRT on our 830 and go through ALL the motions (grabbing some of these apps along the way) ending up on the the latest build of W10M, and these apps still function as they did prior, then why they are doing it is a big mystery and makes no sense whatsoever. Truly believe some of these apps would run on phone's native to 10 perfectly fine yet we'll never know since MS does not give us the ability to do that.