If you are considering upgrading to Sage CRM 2019 R2, which you really should be if you are running on an older version, there are several considerations one needs to make before the upgrade.  

What is the upgrade path? What is supported? Have backups been made, and tested? What changes are required in the environment?  Fear not, Jeff's article covers the essentials.

https://community.sagecrm.com/partner_community/b/hints_tips_and_tricks/archive/2019/08/23/sage-crm-2019-r2-planning-your-upgrade-amp-changes-in-supported-software.aspx

And REMEMBER one of the cardinal rules of computing "To go forward, you must backup"  Anon