One third of Android devices run on the OS KitKat (4.4.4) as of 2013 for a reason – Its matured.
The next updates Lollipop (5.0 in 2014 and 5.1 in 2015 ) then Marshmallow (Oct 2015) and now already the next update is cooking up.
But who needs it, who wants it and where is the “No Thanks, i’m good. Please don’t ask again.” button?
I personally may be old fashioned, but i like the KitKat style and menu structure best. And after i saw other upgraded phones i pulled the brake and spend quite some time hacking my phone to get off the annoying “you urgently need to upgrade now” hook.