Upgrading RabbitMQ can be considered in two directions:
Upgrading the Erlang installation
Upgrading the broker installation
In both cases, it is good practice to perform a full backup of the RabbitMQ broker before performing an upgrade. Also you should check out the release notes for all the versions issued between the old and the new version to see if there are any specific steps that must be performed during the update. Typically, installation of a RabbitMQ broker preserves data and updates only the RabbitMQ installation and the database structures used for representing the broker metadata and message stores. It is important to make sure that, if you have to update nodes in a cluster, you first stop all nodes and use the same version of RabbitMQ for the update over all nodes in the cluster.