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.