We have upgraded to 25-user Atlassian Jira/Confluence wiki since early this year for our engineering department, starting from 10-user licenses last year and I already have to update Jira core which is overwhelming!
@Mehran_Moss you can get tons of help on the community! Here is our Jira Core collection with over 12,000 posts worth of information, and you can always ask our experts a question there. Glad you're here!
@Mehran_Moss - Good luck! These are the type of conversations we like to bring to our User Group meetings. We recently had Mark Williams from Atlassian present on this very topic. I happen to have his presentation on Upgrading Server best practices. Email me at daniel . judd @ atlassianusergroup.com and I can get that over to you.