There's a fork of QK called QUIK if you like that app but want something more updated. I personally use fossify though.

Just to thow in the mix. I think QKSMS is dead, or atleast rarely updated.

Another fork is providing updates via https://github.com/octoshrimpy/quik

I still use QKSMS coz I CBF migrating till i get a new phone.

QKSMS has less active development but I don't think that's an issue as it works well as is. I haven't dug too deeply into the more advanced stuff but I've yet to have any issues with it.

So it seems qksms isn't being maintained, but also I've been using it since signal dropped sms support, and it's been zero problems for me

To my knowledge QKSMS/Quik tries to do something way bigger, like multiple protocols.

I recommend DekuSMS. They have AES encryption for people both using the app, and it just works well.

I've never used Fossify SMS, so I can't really comment on it, but I've been using QKSMS as my default messenger for a few years now and I quite like it. The feature that keeps me on QKSMS is exporting and importing text messages. It's a godsend when you're changing phones.

Does anyone know of a FOSS app that groups messages into tabs? Similar to what SMS organizer does?

Fossify has search so I'll be switching to that probably. People get annoyed when I ask them stuff they already told me.