Minor operating system and application updates can be installed with the regular update procedure (see Minor updates). Sometimes however an upgrade to a new major version cannot be performed that way. This can happen for example if the underlying OS needs to be upgraded to a new major version, like the upgrade from CentOS 7 to RHEL 8.
Upgrading from Gateway version 4 to version 5 and from Webmail Messenger version 3 to version 4 requires migrating to a new virtual appliance because the underlying OS has been changed from CentOS 7 to RHEL 8.
If the regular update mechanism cannot be used, the only way to upgrade to a new major release is by installing a new virtual appliance and importing the data from the old virtual appliance into the new virtual appliance.
Not all settings can be imported between major versions without some manual checks, because there might be changes between system applications which are not compatible. Settings which don’t get exported automatically are: MTA (Postfix) configuration files, TLS certificates and private keys, and network configuration. These settings have to be migrated to the new virtual appliance manually. Users that are familiar with our Ansible automation playbooks will find it easier to perform these steps.
The upgrade procedures differ slightly between the Gateway and Webmail Messenger.
- Upgrading the Gateway
- Upgrading Webmail Messenger