I've to migrate many ATA186 from existing CUCM 3.3 to new CUCM 7.1 cluster (with new IP addresses).
For test, I tried to register a new ATA on CUCM 7.1 and it works.
For the migration I imported the existing ATA configs on CUCM 7.1 and everything seems ok. The problem is that even if I changed the TFTP setting of the existing ATA to the new TFTP server, the existing ATA doesn't seem to contact the new TFTP server and continue to register on the older CCM. I tried a ATA factory reset, but the problem wasn't resolved, too.
Do you have any suggestions?