A user reported that Sutido couldn't connect to their MongoDB 4.0 server. The error wasn't ours — it was the driver's: modern MongoDB drivers have dropped the wire protocol that servers 3.6 and 4.0 speak. Our fix went against every instinct: we downgraded.
The Reality of Old Servers
In real companies, databases don't get upgraded because a client tool wants them to. That 4.0 replica set powering a legacy system? It works, it's stable, and nobody is touching it. A database client that refuses to talk to it isn't principled — it's useless for the exact situation where you need a good client the most.
The Trade-Off
MongoDB driver 7 (which we'd just upgraded to — two weeks earlier, of course) speaks to servers 4.2 and up. Driver 6.9 still speaks to 3.6 and 4.0. For 0.9.1 we made the pragmatic call: pin the driver to 6.x and keep every server reachable.
Where This Is Going
The downgrade costs us newer driver features for newer servers, so it's not the final answer. The plan is a dual-driver setup: ship both driver generations and negotiate the right one per server, automatically. That work is underway — until then, every MongoDB from 3.6 upward connects out of the box.
Update, August 2026: the dual driver shipped in 0.10 — modern servers get the modern driver, legacy servers get theirs, and nobody has to think about it.