I've upgraded my 2821 to 15.0(1)XA to try out CME 8.0. I have a SIP trunk coming in from an ITSP and everything works fine using 12.4(22)YB4. When I upgrade to 15.0(1)XA, DTMF stops working on 90% of my calls (I am forcing RTP-NTE). I have not changed the config between 12.4(22)YB4 and 15.0(1)XA at all.
Tech support tells me that they are receiving RFC2833 packets but they're too short - according to them, the 3 first packets have 0ms duration, the middle packet has 400ms duration and the last 3 have 800ms. They have suggested that I send inband DTMF instead, but I am not really inclined to do that because it worked before. I've tried specifying the payload setting (101) and other settings on my dial-peers to no avail. I have been forced to return to CME 7.1 because of this.
All my phones are SCCP and this problem is reproduced on a broad range of phones including analog phones off a EVM board (SCCP-controlled).