I always forget that my access points have basically the same OS so when I update my Mikrotik router, I tend to forget to prepare the updates of my access points as well.
This blog post helps myself to do it better next time.

# Version to upgrade to
VERSION=7.22

# Make sure that your CAPsMAN path is set. For example you can set it to "/firmware":
/caps-man manager set package-path=/firmware

# Check for updates and note the latest version:
/system package update check-for-updates

# Download the firmware for the access points:
/tool/fetch https://download.mikrotik.com/routeros/$VERSION/wireless-$VERSION-mipsbe.npk dst=/firmware/wireless-$VERSION-mipsbe.npk

Note: If the directory “/firmware” doesn’t exist, it will be created via the fetch command, nice!