Hi There! We had similar problems, using Cisco VoIP phones.. 7921, 7925, 8821.. no one work well after we update version on APs. I mean, we had good performance on 25.9, but when we update on 25.11, we lost that good performance on VoIP phones. after a 10, 15 secs, we lost voice on phones, we saw the dashboard, we could see good level and equipment connected, but no service. At the end, we found version problems, so we made a downgrade, we returned from 25.11 to 25.9. We are using APs MR42 and MR52. Now, net IP voice is working very well on 5 GHz Band.
... View more