Debian RC versions appear more recent than released versions

apt-get does an alphanumeric comparison, so 8.3.0-ce appears to be a downgrade of 8.3.0-rc3.ce.0:

$ sudo apt-get install gitlab-ce=8.3.0-ce.0
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be DOWNGRADED:
  gitlab-ce
0 upgraded, 0 newly installed, 1 downgraded, 0 to remove and 329 not upgraded.
Need to get 405 MB of archives.
After this operation, 904 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Fetched 405 MB in 19s (21.2 MB/s)
dpkg: warning: downgrading gitlab-ce from 8.3.0-rc3.ce.0 to 8.3.0-ce.0
(Reading database ... 320978 files and directories currently installed.)
Preparing to unpack .../gitlab-ce_8.3.0-ce.0_amd64.deb ...
Unpacking gitlab-ce (8.3.0-ce.0) over (8.3.0-rc3.ce.0) ...
Setting up gitlab-ce (8.3.0-ce.0) ...

The Debian version scheme is described here. Note that you cannot count on RPM having support for the Debian-style tilde versioning. Several distributions disable this feature.

I propose the naming scheme be structured in a way that makes the upgrade transparent. For example, this is what Fedora uses:

http://fedoraproject.org/wiki/Packaging%3aNamingGuidelines#NonNumericRelease