I'm an avid fan of Groupy and the concept of it, and use it a lot, but I... haven't heard of any updates in a long time.
My speculation is that Stardock might be behind the scenes reworking Groupy entirely to better accomodate Windows 11 and, who knows, provide a more seamless integration with things in Win11 that already have tabs now, such as File Explorer, Windows Terminal and Notepad.
I believe the more "rounded" style of tabs that these Microsoft implementations have would be excellent to have, given they, well, look more like tabs visually, and the current "rectangular" tabs in Groupy kinda clash with the general look of Windows 11.
Before this gets into "feature request territory", I could provide something like a mockup of what this could look like in, say, a program like inkscape, which I use with groupy a lot:
Now, there's probably just one feature that I would like to see, I think:
-When you enable the "+" button for any given application, all it does is launch a new instance of the program, but there are a handful of software that open new windows (without creating a new instance) when you click something like "New document/something", and usually those are attached to a hotkey, so my idea would be to customize what the "+" button does, so that, by default it launches a new instance of the program, BUT you can configure it so it just sends a hotkey for the "New (thing)" command.
...and that's it really.