Cannot upgrade firmware on HAP AC2

RouterOS General
1

This is on one of my routers:

/system routerboard> print 
       routerboard: yes
        board-name: hAP ac^2
             model: RBD52G-5HacD2HnD
     serial-number: ************
     firmware-type: ipq4000L
  factory-firmware: 6.44
  current-firmware: 6.49.4
  upgrade-firmware: 6.49.4

This is on another:

/system routerboard> print 
       routerboard: yes
        board-name: hAP ac^2
             model: RBD52G-5HacD2HnD
     serial-number: ************
     firmware-type: ipq4000L
  factory-firmware: 6.43.10
  current-firmware: 6.48.6
  upgrade-firmware: 6.48.6

I’m familiar with /system package upgrade check-for-updates menu, but there seems to be no such thing for routerboard firmware.

How can I check and install the latest firmware?

2

That was a dumb question. I realized that one of them is on long-term branch, the other is on stable.

3

Your firmware is already in line with the package installed for that device.
Nothing to do.

Ps there are no dumb questions. Only dumb answers.