If you are using version 3.3 or later, you can upgrade directly to the latest version of Traccar. If you're using an older version, please check details at the bottom of this page first.
If you are using versions 3.0 to 3.2, you have to upgrade to the version 3.3 first before upgrading to the latest release.
If you are using version 2.x, you would have to manually migrate the database schema. See update from 2.x to 3.0 for more details.
Above instructions are made with assumption that only the main configuration file is modified. If any other files (e.g. templates) are changed, you need to re-apply those changes on top of the new version. Note that old templates are not guaranteed to work with a new version.