This is one for those of you like me who get a little forgetful, or maybe belong to a larger team and sometimes trip each other up.

If you upgrade a Yealink phone’s firmware using its WebUI and it immediately downgrades itself again, just check someone’s not previously loaded and Approved a firmware version in Lync/SfB.

Get-CsDeviceUpdateRule | ? {$_.Brand -match "Yealink"}

In my Lab I had (some time back) approved the .cab version of 35.7.0.50 & after I manually upgraded it to 35.8.0.20 it IMMEDIATELY downgraded itself back to 35.7.0.50. Removing the device update rule stopped this happening and let me get the later version installed.

If you’ve not seen it yet, check out Randy’s comprehensive review of the T48G running v35.8.0.5 firmware.

– G.