How do you determine which HP switch firmware is most appropriate?

We have a few HP 3810M switches, and I know the firmware is not up-to-date. However, when looking at the firmware list there are several different "current" versions. For instance, all firmwares listed here begin with KB.16. but then the second number appears to be a "branch" and the last number seems to be the patch level. But if we are currently running a KB.16.04.* firmware then should we select the latest KB.16.04.* version? I assume that would be the "safest" option, but it's not immediately clear what the tradeoffs are. Since these are all listed as available for this switch, can I update to any of them? Is there any summary of what is new in each "branch" version, or would I just need to read through all the release notes for the different versions to figure that out?

Update:

I ended up updating to the latest release for the branch on one switch stack, and that worked fine as expected. I then used the activate software-update command to update a different switch and that used the latest branch (10) and since that also worked without any apparent issues I put that same version on the first stack.

It would still be nice to have a more definitive summary and guideline for selecting the recommended firmware, though.

You're pretty much right: with KB.jj.ii.bbbb, KB indicates the switch series, jj the major release (releases may differ considerably, web interface changes, command changes), ii the minor release (generally compatible but features may be added), and bbbb is the build/patch level, removing bugs mostly.

Generally, you'd want the latest/greatest. But if you can't even risk the slightest change in behavior and don't want to check the release notes for any changes you stick with the latest minor release build. Unless it's old already, of course - HPE tends to maintain several releases in parallel, but not indefinitely.