How to Upgrade
If you have a previous version of 3CX, and you want to upgrade to V15, make sure you have valid maintenance.
1. Ensure that all Windows updates are installed. (This can be a time consuming process if you have not done this in a long time. So do this before you install V15)
2. Access your current 3CX Phone System and perform a backup
3. Uninstall 3CX
4. Download and install V15
5. The 3CX PBX Configuration tool will launch and will prompt you to restore your previous backup. Enter the path including file name where your backup is saved. The license key inside the backup will be used and linked to this installation.
6. You will be prompted to choose a 3CX FQDN or import an existing SSL Certificate for a domain that you already own covering the chosen FQDN. If you choose a 3CX FQDN, choose your hostname wisely because the license key will be bind to the chosen FQDN.