There doesn’t seem to me anything in the documentation or release notes about upgrading.
Upgrades are not supported. We generally recommend new installs and migration of data. There is a tool called elevate, but we have not vetted it nor tested it to know if it works.
You can see my comment on reddit that shows why upgrades can be potentially dangerous and problematic.
Thanks! Is this something that could be supported in the future?
About the future, people will create all kinds of elaborate tools for this, but in the end it’s much better to do a clean install.
Indeed. The ELevate is likely to support EL8->EL9 in the future, but no tool can migrate all EL8 systems – there are always impossible corner cases.
Besides, there are many scenarios other than migration to different distro where one will have to resort to clean install (and restore of data from backup). If you do have such routine at hand, as we all should, it can be used for “migration” too.
Configuration management systems are tools that make reinstall easy.