Here is a new update for Google Now on Tap feature for Android M preview deices only.This will not work on Android lollipop 5.0.1 o 5.1.1 not even think it to run on android kitkat.Google finally released Google Now on Tap that is the biggest feature of android M 6.0 Marshmallow features but it is limited to some users who are using Android M developer preview in there Nexus devices .you can download the latest version of Google now on Tap ( Google launcher )from Below link.
If you install this on earlier version of android that is
lollipop and kitkat but think of working Google Now on tap Feature as
it is only for android M 6.0 at least for now.You can wait for an update
to hit on google play store or you can download it directly from below
link.
I have a newer version of google now on my note 4..but don't have now on tap…why
Now on tap only works on Android marshmallow.