need method to set properties in groovy code

Some possible workarounds:

I think LM Config might be the better option for this, although I haven't played with it personally yet. It's designed for config files, but I don't see why the "config" file can't just be the version info.

Also rather than attempt to use properties to store state, you can try using a file on the collector, for example "../tmp/firmware_${hostname}.LastRun" then it would be easy to read in the script. There might be an issue if resource bounces around collectors though.

You might also be able to using Auto Discovery Instances with DataSources, which lets you set auto properties, but that might be tricky to implement.