We have a zd 1100 and multitude of zf7372 aps on our network. We would like to upgrade our environment to an on-prem virtual controller and R510 aps. Can we setup progressively in parallel the new environment with the same ssids to ease the implementation instead of working weekends and to eliminate downtime then pull out the zd1100 and zf7372 aps?
Of note, roaming will not occur between AP's on on different controllers seamlessly so there will be issues with latency sensitive traffic such as VOIP.
You should also make changes to DNS and DHCP options to advertise the vSZ rather than the ZD. As the existing AP's already know about the ZD they do not need this unless they are factory reset. Either that or manually set the vSZ on each R510.
One last thing is to ensure that WIP is off or at least "Protect the network from malicious rogue access points." is not enabled on both systems as they can attack each. unless you want to manually mark all AP's as friendly.