Adding a few of the questions you mailed me directly with.
> It seems our Trac originally ( way before my time) was installed using Bitnami who seem to no longer support trac. So wanted to see any recommendations you might have in terms of proceeding to try and upgrade Trac as it all seems to be bundled into a Bitnami installation.
The main thing you need from the old installation is the environment directory. It is described here:
You can copy it directly or use the tooling:
> Also where would I see installed plugins to remove them in this case as needed for various versions? I'm planning to go from 1.0.9 to 1.2 first just as i'm new to this and then eventually to 1.6.
Plugins can be viewed on the /admin/plugins page, the /about page, or in the environment plugins directory (provided you don't have a more complex installation with a shared plugins directory.
> What would you recommend as the best way to approach this?
> - a fresh install and import backups?
I would create a fresh install, copy over the environment, and run the upgrade steps.
> - follow the upgrade guide even though it was installed as a bitnami stack?
Yes, for the most part it shouldn't matter that the old installation was Bitnami.
I haven't tried it, but Turnkey Linux appears to be similar to the Bitnami appliance, so you may find that useful: