I recently upgraded a remote site of mine to IOS 15-2.SE ipbasek9 on 3 3560E series switches. On switch number 2 I have 5 VG224's running (vg224-i6k9s-m) 12.4(22)T3. After the switches reloaded the VG224's dropped their connection. After doing all basic troubleshooting I reloaded the 12.2 (58)SE2 ipbasek9 image back on to the 3560E's and the VG224's reconnected immediately after reload and all phones registered.
Is the problem a licensing issue with the 15.x IOS on the 3560's or do I need to upgrade the VG224's to IOS 15.x as well for them to connect and operate via the 3560e switch running 15-2?
Anyone seen this before?