Dear Grandstream Customers,
Firmware 1.0.9.22 for GRP2612/2612P/2612W/2613/2614/2615/2616/2624/2634/2670 is now released as Beta. Here is the link to the release notes:
http://firmware.grandstream.com/BETA/Release_Note_GRP261x_1.0.9.22.pdf
The firmware and release notes can be downloaded from:
Please contact us should you have any issues. Thank you for your support for Grandstream products.
Technical Support
Grandstream Networks, Inc.
At first account I have to remove the registration hook to get it registered to UCM.
If I enable it, the phone shows “not allowed” at the line account1.
It seems its really a beta version 
EDIT: I think its a provisioning issue beacuse there´s no exact template availible
This firmware (including the now official release) breaks custom softkey latyouts!!! (the keys under the lcd)
Cannot be restored using GDMS… Only via the phones web UI.
We have many sites where LDAP search was set to one of these buttons. Grandstream were made aware of this problem by myself back when it was Beta. they went ahead and made it official, the phones updated overnight and copped calls from quite a few customers the next morning.
Grandstream have still not fixed the bug.
I had the same issue, seems they changed how to configure. Try this solution: