Update Tiaga to latest version

[jacoblijo]

Hello,
I need to upgrade taiga to latest version 3.3.3 from 1.8 on the production server.

-->> Do I need to follow the default upgrade process or any other steps.

-->> While executing the git pull for both the front/backend application,will the internal config changes
that was done like maild id domain port number etc change along with it or will it remain
unaffected.

Any suggestions will be highly appreciated.

Regards
jacob