As I understand - IP Touch will be upgraded automatically (from PBX depends of release)
I1.605.14e - 4.20.60
I1.605.16c - 4.20.70
I1.605.21 - 4.21.00
Just commect set to PBX with right binaries.
Look at this topic :Board index ‹ VOICE - Common topics for Crystal / Common hardware ‹ Bugs & Security issue /Problem download binary to 4038
As you can see there are more problems with the Ip touch phones