It can be a pain managing previously downloaded PANOS software images. Especially on the smaller firewalls with limited storage, the old versions just take up valuable space. Rather than using the API to do this at scale, one option is to limit the number to versions each firewall will keep at download time:
set max-num-images count 2
Now at download time only two active images will be kept, where the number is the amount you want to keep. The current setting can be found by the following:
show max-num-images count 2
Which on a PA-220 looks like:
[email protected]> show max-num-images
Maximum images to keep is set to 2
This way each firewall will never build up a back catalogue of pointless old OS software.