We are excited to announce a new and improved user interface on Microsoft Teams phones. These experiences are now available to all users as a firmware update through the Teams Admin Center today. The...
Updated Jan 26, 2021
Version 4.0
Blog Post
ashb_79 You cannot upgrade the phone directly from 1.0 to more recent 6.x versions. You need to first perform an upgrade from 1.x via USB to version 6.2.22.0185 specifically.
Download the "Poly CCX 400 1.0.X to Poly UCS 6.2.22.0185 USB Upgrade (Teams)" firmware package shown on the on the CCX 400 support page:
Once you complete that upgrade then you can use any supported upgrade method (like the Teams Admin Center) to get to latest supported version.