This was mentioned in another comment already, yet I’m explicitly looking for a “non-invasive” solution.

I know, that’s why I don’t even bother with looking for a more beefy card.

It has, and I use this setup for years already. Thought about tinkering a bit, y’know? :-)

Thank you very much!

Thank you for the recommendation, but I would prefer not to tamper with the board.

It requires an x16 slot though

It seems to be indeed Mattermost as a service 😀

No, if it is too complicated for me – it will be too complicated for 95 % of our potential “users”.

I’ve mentioned Rocket.Chat in my initial post, and isn’t Stoat “just” Revolt?

It seems Zulip is the Slack alternative you wish for?

Sadly there is nothing you could call an IT budget. As with many small-to-mid-sized institutions.

Ugh, also looking for a way to digitalize mine, but all tools I’ve found are either way too complex or lack critical functions, like e. g. supporting patchwork families/split-up parents which have new children.

Thank you, updating the firmware was the issue. Added this to the Original Post. :-)

As Sonoff doesn’t seem to offer invoices, I’m not sure if it is a ZBDongle-P or -E, but I will check out updating its firmware, good thinking!