Note 5 spen features for note 4 5.1.1

I am on 5.1.1 COH4 and it's running mote stable, faster, snappier and just everything is so much better then the old versions of android so why are people still stuck in the old versions and developing???

Why isn't some Developer or anyone with the knowhow porting the note 5 spen to note 4 5.1.1 COH4 ?

There must be some of these people using 5.1.1 ?

Also is anyone working on porting note 5 rom over ?

I am willing to be a test subject if needed...