I imagine there's a simple answer to this but I haven't been able to find it so far.
I have a network consisting of some old gear - an MX64 and an MS220-8P
They're currently running 15.42.3 and 14.31 respectively (stable releases).
If I look under Organisation -> Firmware Upgrades, I can see available upgrades to MX 15.44.3 and and MS 14.33 (both stable releases).
When I look under Network Wide -> General, there's no "Upgrade as Scheduled" option for Switch or Security Appliance. The only options available are "Schedule for ...", "Perform upgrade now" or "Ignore".
Access Points and Cellular Gateways have the "Upgrade as Scheduled" option.
Is there something I'm missing or is this simply due to having old equipment in the network?