I'm trying to work out why the S6 is unsupported. Funnily enough, I just helped a friend put 14.1 on their G920i, but I didn't realise it was so far out of supp

I'm trying to work out why the S6 is unsupported. Funnily enough, I just helped a friend put 14.1 on their G920i, but I didn't realise it was so far out of support. I also don't know why a faulty / for parts S6 still goes for ~$150 here in Australia.