4. Post-upgrade checks
When you upgrade XenForo, we will not automatically overwrite any template or phrase customizations you have made. You should check if there are any outdated entries here under Appearance > Outdated templates and Appearance > Outdated phrases. You can use the template merging tools to attempt to automatically incorporate the core changes into your customizations.
If you are using a third-party provided style or language, you may wish to see if they have a release that is designed for the version of XenForo you are now running.