Hi,
This is essentially an issue, but IMHO it can be addressed by either avoiding the upgrade or checking the CPU Features:
grep flags -m1 /proc/cpuinfo | grep avx
So I hope this serves as an additional piece of information to consider before proceeding with any upgrades of RocketChat with MongoDB 5.0+ included.
In my case after an actual upgrad to:
rocketchat-rocketchat:6.5.2
rocketchat-mongo:6.5.2
The Rocketchat Login stop working with:
Checking with:
docker ps |grep rocket
shows a permanent restarting mongoDB:
and looking into that with:
docker logs your rocketchat-mongo CONTAINER ID
shows the problem:
WARNING: MongoDB 5.0+ requires a CPU with AVX support, and your current system does not appear to have that!
including some infos to the problem:
https://jira.mongodb.org/browse/SERVER-54407
I will leave it as is for now, you are informed 
