I have configured and working CAPSMAN on RB951G-2HnD, now I want to replace RB951G-2HnD with hap ax3, BUT in winbox there is missing CAPSMAN configuration, however in CLI there is, but only for wifiwave2 (or maybe I misunderstanding that). So I want to move my CAPSMAN to CRS354-48G-4S+2Q+. I simply exported and imported its config. All seems nice. But when I change CAPSMAN IP address on my cAP ac device to IP address of a new CAPSMAN, it still connects to the old one. I don't know why. I can ping from cAP to CRS, I don't know where could be a problem. Any advice please ?

In the cap settings, enter the server search by ip address only or list several. The cap connects to the first in the list, if it is not available then connects to the next (backup)
The field Discovery interfaces must be empty, otherwise it will search by MAC

Thanks a lot. That was the magic: The field Discovery interfaces must be empty, otherwise it will search by MAC

No magic. In ROS, all rules are handled from top to bottom. If an interface is selected for searching, first the MAC on that interface is searched and only if it is unsuccessful will the next rule and start searching by IP

I'm not sure this order (first MAC, then IP) is about the order. I'd say it's by design, autoconfiguration only works via broadcast/MAC and that's the way vast majority of installations are supposed to work. And it's the only way possible when "configuring" AP into CAPsMAN mode by performing mode button press magic. Also having CAPsMAN on local LAN offers slightly higher possibility to have APs running without hiccups as they need constant connectivity with CAPsMAN manager - in routed environment there are additional points of failure. Having possibility of setting both discovery interface (for L2) and IP address(es) by itself offers a path to set-up baclup CAPsMAN manager(s) outside L2 for resilience.

The use case of OP - "smooth migration" from one CAPsMAN manager to another whike both are connected to same L2 network, is a border use case, specially as he wants to prioritize one and/or phase out the other one while keeping the other one on-line (which begs for explanation of reasons for doing it this way). And that's something that has to be fine-tuned ...

I just simply want to move all my cAPs from one CAPSMAN to a new one and then remove CAPSMAN on RB951G-2HnD and then replace with ax3.
So I don't really need any prioritizing.
Since I am using mgmt vlan on all Mikrotiks I always used Discovery interface vlan99, which was not good in my situation. Now I know that, when I have Discovery interface filled it will run using MAC address and I don't need to fill up IP address of CAPSMAN. Not sure of bennefits of using MAC address on CAPSMAN connections or IP address ?

With the transition to ax will have to wait because the new Capsman wifi wave 2, does not yet support older devices.
There is practically no difference in connecting by MAC or IP. Since there is a proprietary encrypted tunnel between the manager and the access point and further communication takes place within it.

I just simply want to move all my cAPs from one CAPSMAN to a new one and then remove CAPSMAN on RB951G-2HnD and then replace with ax3.

CAPsMAN has this redundancy built in: if there are multiple managers available on L2 network, any of thrm can provision CSPs ... prerequisite is that configuration sent by any of them is compatible with the other one. If one of them fails, managed CAPs will drop wireless interfaces and look for another manager. WiFi network will be down for a few seconds (or 10 minutes if DFS channels are in use).

So if you want to replace old CAPsMAN manager with a new one, simply add the new one (make sure configuration is fine) and then stop CAPsMAN service on the old manager device. All APs will loose connectivity to their manager and will thus look for another one .. which wiil be there and will gladly provision all of them. So the whole wireless network will flip, but no configuration change on CAP devices is necessary.

As mentioned in previous post, ax3 CAPsMAN manager can not (yet) provision legacy (non-wifiwave2) clients.

I was a little bit scared of that scenario, so I preffered migrate cAP one by one.

As mentioned in previous post, ax3 CAPsMAN manager can not (yet) provision legacy (non-wifiwave2) clients.

That's why I need to move RB951G CAPSMAN to different device before I will replace it with ax3.