Another (pretty elegant IMO) possibility, which is there in legacy capsman (I don't know if it exists in capsman2): host necessary package files on capsman device and configure capsman to offer them to CAP devices.
Example:
- add some storage to capsman device, an USB stick will do. Get it mounted (for the education purposes I'll assume it'll be mounted under /disk1, in v7 reality it'll be something in line of /usb1-part1 or some such)
- create directory (e.g. packages) ... CLI (AFAIK) doesn't offer this possibility, so you have to retort to other ways (FTP connection to ROS device allows running mkdir command). Then copy all necessary package files to that directory. They have to be for architecture of CAP devices. It's safe to copy main package file as well as all of package files from "Extra packages" ZIP archive. CAP will only pick package files it needs for upgrading.
As far as my experience goes it's safe to mix files for different ROS versions as well as different architectures.
- configure capsman, point it to package directory, e.g.
/caps-man manager
set package-path=/disk1/packages upgrade-policy=suggest-same-version
This will try to upgrade CAP devices to same version as CAPsMAN. To make things trully automagical, you have to make package files for CAP devices available before you upgrade CAPsMAN device itself. In this case ... after CAPsMAN device upgrades, capsman process will make CAP devices to upgrade right after.
The "
suggest-same-version" part is there to offer upgrade but allows CAPs with other verdions to work with capsman regardless. The other option ("require-same-version") is way more brutal - if upgrade of CAP doesn't succeed, then CAP is left in void (until manual fix of the problem).
One thing is then missing in the picture above: updating routerboot. To automate this as well, you have to change setting on CAP devices manually (once and forever):
/system routerboard settings set auto-upgrade=yes
or you can manually update it from time to time.
And the problem you currently face: different generation of ROS on CAPsMAN vs. CAP devices. As a precaution I'd manually upgrade one of CAP devices to v7.8 first to verify that it still works fine as CAP after upgrade to v7. If it does, then follow the procedure above and observe the other CAP get upgraded.
@holvoetn: if CAP devices don't have any L3 config (hence management is not possible via IP), then they won't be able to check for upgrades as per your suggestion. The only manual way would be to connect using winbox via MAC and upload package files ... then reboot devices and if all package files are there, device would upgrade at reboot.