GitLab 7.5 -> 7.83 (Latest Version) Update Error

Hi GitLab,

I’ve recently upgraded from 7.5.3 using the upgrade instructions located here: https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/update/upgrader.md

Sidekiq wont actually start after the upgrade – see below:

root@git:/home/git/gitlab# service gitlab restart
Shutting down Unicorn.
GitLab is not running.
Starting both the GitLab Unicorn and Sidekiq…Waited 30s for the processes to write their pids, something probably went wrong.

log/sidekiq.log

undefined method `merge' for #<String:0x007f34079fb720>
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/sidekiq-3.3.0/lib/sidekiq/cli.rb:357:in `parse_config'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/sidekiq-3.3.0/lib/sidekiq/cli.rb:207:in `setup_options'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/sidekiq-3.3.0/lib/sidekiq/cli.rb:38:in `parse'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/gems/sidekiq-3.3.0/bin/sidekiq:7:in `<top (required)>'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/bin/sidekiq:23:in `load'
/home/git/gitlab/vendor/bundle/ruby/2.1.0/bin/sidekiq:23:in `<main>'

Environment check

root@git:/home/git/gitlab# sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production

System information
System: Debian 7.8
Current User: git
Using RVM: no
Ruby Version: 2.1.2p95
Gem Version: 2.2.2
Bundler Version:1.6.5
Rake Version: 10.3.2
Sidekiq Version:3.3.0

GitLab information
Version: 7.8.3
Revision: abea070
Directory: /home/git/gitlab
DB Adapter: mysql2
URL: https://git.hidden.com
HTTP Clone URL: https://git.hidden.com/some-project.git
SSH Clone URL: git@git.hidden.com:some-project.git
Using LDAP: no
Using Omniauth: no

GitLab Shell
Version: 2.5.4
Repositories: /home/git/repositories/
Hooks: /home/git/gitlab-shell/hooks/
Git: /usr/bin/git

Thorough Environment check

root@git:/home/git/gitlab# sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production
Checking Environment …

Git configured for git user? … yes

Checking Environment … Finished

Checking GitLab Shell …

GitLab Shell version >= 2.5.4 ? … OK (2.5.4)
Repo base directory exists? … yes
Repo base directory is a symlink? … no
Repo base owned by git:git? … yes
Repo base access is drwxrws—? … yes
Satellites access is drwxr-x—? … yes
hooks directories in repos are links: …
HIDDEN … ok
HIDDEN … ok
Running /home/git/gitlab-shell/bin/check
Check GitLab API access: OK
Check directories and files:
/home/git/repositories: OK
/home/git/.ssh/authorized_keys: OK
Test redis-cli executable: redis-cli 2.4.14
Send ping to redis server: PONG
gitlab-shell self-check successful

Checking GitLab Shell … Finished

Checking Sidekiq …

Running? … no
Try fixing it:
sudo -u git -H RAILS_ENV=production bin/background_jobs start
For more information see:
doc/install/installation.md in section “Install Init Script”
see log/sidekiq.log for possible errors
Please fix the error above and rerun the checks.

Checking Sidekiq … Finished

Checking LDAP …

LDAP is disabled in config/gitlab.yml

Checking LDAP … Finished

Checking GitLab …

Database config exists? … yes
Database is SQLite … no
All migrations up? … sudo -u git -H RAILS_ENV=production bin/background_jobs start
yes
Database contains orphaned GroupMembers? … no
GitLab config exists? … yes
GitLab config outdated? … no
Log directory writable? … yes
Tmp directory writable? … yes
Init script exists? … yes
Init script up-to-date? … yes
projects have namespace: …
HIDDEN … yes
HIDDEN … yes
Projects have satellites? …
HIDDEN … yes
HIDDEN … yes
Redis version >= 2.0.0? … yes
Ruby version >= 2.0.0 ? … yes (2.1.2)
Your git bin path is “/usr/bin/git”
Git version >= 1.7.10 ? … yes (1.7.10)

Checking GitLab … Finished

I can revert back to 7.5.3 from the backup created, however I just simply can’t upgrade as it keeps failing to start Sidekiq due to the above error.

Any advice or help would be greatly appreicated.