95% or more of these are due to improperly configure reverse proxies where the WebSocket is not working properly. If a WebSocket cannot be correctly established, the client will try and fall-back to an XHR connection. It is extremely slow and flaky. The iOS app will not connect at all without a WebSocket.
Please use Chrome/ium and dev tools to check for the presence of a WebSocket.
Right Click, Inspect
Network, F5 to refresh
Look for the WS filter
Should see WebSocket
WebSocket - wss://open.rocket.chat/sockjs/123/pbiz45rm/websocket
Click it and look on the right for 'Headers'
Has this got a green light?
Status Code: 101 Switching Protocols
What do the headers say?
Response headersConnection: UpgradeSec-WebSocket-Accept: nXd/PfaHuA1Kx/ggJWAAy+96Ee4=Upgrade: websocket
For upgrading first, you have Rocket.Chat itself, and then the Mongo database.
Snaps should auto-update so this is aimed at those who use other methods.
Rule One. Backup. Lots of them and lots of ways, and practice restores as well.
Rule Two. Use virtual machines for testing. They are so cheap.
Again backups! Please read how to do this. Practice it.
Use the Mongo documentation. There are leaps between 2.x and 3.x
Then there are more leaps as you proceed trough 3.x and then again to 4.x
As of writing 3.4 is going EoL so you need to be on 3.6
For now I would get to 3.6 and then start preparing for 4.x
To convert from mmapv1 -> wiredtiger you will need to backup, convert, restore
Did we mention backups? Yup - boring. Until you need them. 😉
Most Roket.Chat updates also update the database schema - the core layout.
Now, theoretically apart from adding oplogs to Mongo for Rocket 1.x + you should be able to merrily jump from say 0.62 through to todays 2.1.x
Except..... those schema changes. If you are going to hit a problem, it will be one of those.
The devs test changes from one version to another, and maybe even over a few versions. But not every single version up to latest or say 0.74.3 -> 1.3.2
That's where it may go wrong.
So a recommended path is something like this:
-> 0.73.x -> 1.0.x -> 1.32 -> 2.0.x -> 2.1.x
Or possibly even more cautious:
-> 073.x - 1.0.x -> 1.1.x -> 1.2.x -> 1.3.x -> 2.0.x -> 2.1.x
We have seen people make some big jumps. And some disasters too. If in doubt, take your time and a backup!😃