Upgrade gitlab

I have gitlab 7.5.3
How to upgrade to the latest version ? Any guide?
[root@gitlab ~]# dmesg | grep “Linux version”
Linux version 2.6.32-431.el6.x86_64 (mockbuild@c6b8.bsys.dev.centos.org) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-4) (GCC) ) #1 SMP Fri Nov 22 03:15:09 UTC 2013

Hello matriarx,

Sure, i could help you on this, to provide you steps i would need below info.
Is it a ominbus or a non-omnibus installation?

by running below command you can confirm the installation type, It would be great if you could post the output here.

to check the gitlab environment information(as well as installation type):
gitlab-rake gitlab:env:info

to check the gitlab environment information(Source method)
sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production

You can remove your server hostname from the output for security reasons.