Hardik
They can. It’s pretty easy to implemented, many ideas with different button setups was also made by the community. It’s a cheap excuse (no dedicated key and the software is designed around that key).
They simply don’t want to, because why should they invest develop time (which they obviously don’t have much) and money to implement it in older phones? They lose selling points for the newer devices, need to adapt it to older and it costs money to run it…
Understandable but sad
AryanKhatua
There is a community made app that supports it, if you want I can sent you the post
rlamim
Just take a normal screenshot
