berkinet wrote:I have searched, but been unable to find, any specific instructions regarding upgrading from homebridge-indigo to HomeKit Bridge
Homebridge Buddy was developed initially as a management tool for Homebridge-indigo, so there's no migration path from one to the other. It then became a self contained version of Homebridge-Indigo and now has been rewritten as HomeKit Bridge. Confused yet?
berkinet wrote:I assume I must stop homebridge-indigo from loading with launchctl (using a launch agent). Right?
You don't
have to, you can run both side-by-side, which may be preferable so you can slowly migrate between the two. Eventually I think you'll want to stop it from running automatically though just because if it's not in use then why continue to run it?
berkinet wrote:From a quick look at the HomeKit Bridge package, it looks like it contains everything needed, like node.js, etc. Right?
Yes, it is 100% self contained. That being said you may have added Homebridge add-ons to Homebridge-Indigo that are not supported so you may evaluate that first.
berkinet wrote:Is there any way to take advantage of my existing homebridge-indigo (~/.homebridge/config.json)? Or, do I just start from scratch with HomeKit Bridge and redefine everything?
Starting over is really the only way, but you can do it slowly (see two questions above).
berkinet wrote:Are there any other tips or pointers I should know about?
HomeKit Bridge, while quite stable, is beta so know that going into this. The slow migration might be best suited for you so that if something isn't quite 100% you still have your existing setup. For me, I migrated entirely a while ago, as have many - if not most - of the people using HomeKit Bridge. In fact I think that Webdeck, who developed Homebridge-Indigo, has mostly migrated to HKB too.