Future upgrades

[gjh42]

You might want to check this thread: Known Bugs (and fixes) with v1.3.9 as well as the version release threads to decide for yourself.

[DrByte]

Upgrading from 1.3.9a to 1.3.9h is just a very simple matter of replacing the files changed in 1.3.9b and 1.3.9c and 1.3.9d, e, f, g, and h by uploading the latest versions of those files to your server.
If you've customized any of those files you'll want to do that again, but the likelihood of such a clash is rare given that most of the updates are to deep core files, not things typically affected by customizations or addons. That said, you must assess your own.
The list of changed files is, as always, inside the /docs/ folder.

Probably a 1-hour process from start to finish, with a total downtime of maybe 2 minutes.