i expect you will need to do these updates from the command line where ever your forum is hosted. if you don’t have access to the server droplet yourself, you should contact whoever is hosting your forum.
It would be fair to say the interface is confusing. Both the two things need to be updated, but Docker must be updated first, before the other one is possible.
OK – how long should that take? Last time I tried, I ended up exiting out, as it seemed “stuck.”
Just let it run. Depending on forum size. The updating may take a bit.
In my experiences maybe 10 to 15m per item being updated.
It will appear to be paused at times but it is still working on it.
It has been running for over an hour, with no status bar filling up and no visible movement. This is a brand new forum, and hasn’t even been publicly seen yet (only staff is testing it).
It might help to share a screenshot of what you see and where it got stuck. But often if the update in the interface fails, you need to run the update on the server. I am not sure if you have access to that or if you need your hosting provider for it.
I’ve occasionally had the Docker update screen stick on “updating…” – I just gave it 15-20 min (my Docker updates usually take about 10) before refreshing the screen and that found Docker_manager had indeed updated.
If yours sat on “updating…” for an hour you might find the same, or it might need a command-line update as mentioned previously.
Sometimes there will be log messages which are supposed to appear in real time but you need to refresh the page.
Note also that there’s a big blue button you need to press to start the process.
There has been a bug fixed recently to address stalled updates, but I think it shouldn’t apply to a new forum that’s never been updated.
Yes, I did refresh and nothing. Still asking me to update. No idea what a command-line update is and getting no help from our vendor… 
Yes, I did do a hard refresh and still no results. The blue button that says “Update All” is not active for me; only the Docker_manager update button. I have tried three times, left it alone for an hour or so each time, but nothing changes.
It does sound like you need a command line update - that’s not terribly uncommon, so it would be good for you to know how to do it. Possibly your vendor would need to be involved, that depends on whether you have ssh access or console access, which is what you’d need.
Just to clarify my previous remark, the button to start the update is on the next screen after you press the button to update - and it’s not blue:
If you’ve reached that page, and pressed the button, and then waited, it would probably help to paste a screenshot of what you see.
When I click on “Start Updating,” it says “updating” but nothing changes after that, for hours.
Yes, everybody is suggesting a command-line rebuild, because trying a web UI update won’t work at this point. Doing so is required sometimes when docker manager fails to update for you.
As @Moin suggested you could also post a photo of where it’s hanging up.
Sorry – I’m lost; where was that update screen again?? Now I can’t find it.
From /admin/update you see which components have a pending update, and then the Update button takes you to /admin/update/docker_manager