I have sideloaded this firmware on my H2O and Glo. Everything seems to be working fine.

I like the new Homescreen and the authors view.
The first thing I did after the installation was to enable the PIN lock.
I am very happy that the curly braces have been taken back into the keyboard layout. A long tap on one of the round or square brackets calls the corresponding context menu. Except me probably even more users had the missing Kobo complained.