I've had a support request via email which I wanted to answer publicly, just in case someone else has a similar question. Marcos writes:

I need some help. I need to use PostgreSQL v10 on one application and LAPP on TKL isn't ready for this. How should I proceed to update the process of installing Postgres 10 on a TKL template?

As you would be aware Marcos, current v15.x TurnKey has Postgres v9.6. The next release of TurnKey (v16.0) will be based on Debian 10/Buster and will come with Postgres v11 by default. Unfortunately, that will still be a little while away (hopefully only a few weeks, but no promises).

Assuming that Postgres v11 will be suitable for your purposes, then one path you could go down would be to do an "in place" Debian upgrade. That will upgrade your existing server to a Debian 10/Buster base. It's a little messy as we don't yet have our custom software (e.g. Confconsole, etc) published yet, but the current software should still work ok.

To do that, I suggest that you have a read through the official Debian documentation. If you google something like "how to upgrade debian 9 to 10", you'll also find tutorials floating around online which might be also be useful.

Unless you are doing this on a fresh server (i.e. with no user data), I strongly recommend that you take some sort of "snapshot" of your current server before you do any of this. Whilst TKLBAM is a good backup option, the upgrade process will upgrade packages, so a snapshot of the full filesystem is desirable. Or perhaps better still, take a snapshot and do a test run with a new server launched from a snapshot?!

If you have any problems or questions, please post back and I'll do my best to help out.