8821 firmware update to SIP8821.11.0-4SR2-15. after the update phones are not registering to CUCM, please help

[shafianjum]

8821 firmware update to SIP8821.11.0-4SR2-15. after the update phones are not registering to CUCM, please help

[HARIS_HUSSAIN]

Try to downgrade the version back to one which was working. Just change the firmware default in Device>Device Settings>Device Defaults to original.

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Thanks,
Haris

[shafianjum]

Hello,

I have reverted back to the old firmware and it got register.  but how do I get this phone work with the new firmware. My CUCM ver. 11.5

Thanks

[HARIS_HUSSAIN]

Why do you want to Upgrade to that particular version any specific reason? Try the next available version if available

*** Please rate helpful post; Mark "Accept as a Solution" if applicable

Thanks,
Haris