License question about 7920 to 7921 phones

[benharned]

I have some 7920 devices that I will be replacing eventually (one immediately) with 7921G devices.  Currently we run CCM 4.2(3).

Do I need a 7921 with a license or can the 7920 license cover the new 7921?

[David Hailey]

If you have DLU's available on your cluster then you should be able to run the new phone.

[Tommer Catlin]

Technically, it does not matter with CUCM 4.x.  If you purchase a 7921, it comes with the license.

When you finally upgrade to CUCM 7.x, you will be grandfathered into the new DLU licensing scheme.