Failed upgrade: NoMethodError

We have Omnibus GitLab 13.10.2 and want to upgrade to 14.0.12 as the documentation suggests: 13.10.3 → 13.12.15 → 14.0.12 → 14.9.0 → 14.0.12.

The first 3 upgrades worked fine, but we probably didn’t wait enough time for the migrations going from 14.9.0 to 14.0.12 and got the following error (HTTP 500):

NoMethodError (undefined method 'admin_mode' for #<ApplicationSetting:0x00007f1e91065ae8>)

We then restored the 13.10.3 backup and tried to only do one upgrade each day.
But now going from 13.10.3 to 13.12.15 results in the same error.

Any suggestions?

I have exactly the same situation
Did you manage to solve it somehow?

We were able to do the upgrade.
The only difference was the disabling features step.
Commands used:

docker exec -it gitlab gitlab-rake db:migrate

docker exec -it gitlab gitlab-rails console


docker exec -it gitlab gitlab-ctl restart puma 
docker exec -it gitlab gitlab-ctl restart unicorn

Thank you very much, it helped me a lot.