I believe you can add a parameter to the /devices can to very different device types including groups. I don’t recall the syntax offhand, but if you use developer mode on a browser and request groups in the API Browser+, you’ll see the call.
I never use v1/ in the path as I’ve found it can break things, and because the Core SDK and CLI bods never use it. /devicegroups certainly still works for me without it. I can’t test with it at the moment. Update: but I can now and all is well.
Likewise I only use version numbers in the accept header where I need one of the date based version numbers. I think there maybe one case where I needed v1 in this situation but I’d have to trawl for it.
You can use includeGroups=true to include the GROUP devices in the /devices listing which excludes them by default.
/devicegroups is complementary to /devices and covers the extra handling that groups need on top of the common device handling (similarly you get /hubdevices, /virtualdevices and, it would appear, /irdevices). So depending on what you are doing you may need both.
This works just great! It also means I have one fewer interactions with the SmartThings server and thus my app works faster! Thanks a lot for the info!
(Sorry it took me a while to respond. I needed to take a sudden trip, but I tried this the time I got back.)