After performing a do-release-upgrade as outlined in this post to get from 14.04 to 16.04, it appears to have MOSTLY worked, but I am now seeing this error when trying to view a file with the web interface.
ActionView::Template::Error ('nil' is not an ActiveModel-compatible object. It must implement :to_partial_path.):
It appears that the versions of git are the same:
/opt/gitlab/embedded/bin/git --version git version 2.7.4
which git /usr/bin/git /usr/bin/git --version git version 2.7.4
Current Linux info:
lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 16.04.1 LTS Release: 16.04 Codename: xenial
Current Gitlab info:
GitLab 8.12.7 GitLab Shell 3.6.1 GitLab Workhorse 0.8.2 GitLab API v3 Git 2.7.4 Ruby 2.3.1p112 Rails 184.108.40.206 PostgreSQL 9.2.18
Also, this is for the Omnibus edition.