<h3><a id="upgrade">1.5 Upgrading From Previous Versions</a></h3>
<h4>Upgrading from 0.8.0 to 0.8.1</h4>

0.8.1 is fully compatible with 0.8. The upgrade can be done one broker at a time by simply bringing it down, updating the code, and restarting it.

<h4>Upgrading from 0.7</h4>

0.8, the release in which added replication, was our first backwards-incompatible release: major changes were made to the API, ZooKeeper data structures, and protocol, and configuration. The upgrade from 0.7 to 0.8.x requires a <a href="https://cwiki.apache.org/confluence/display/KAFKA/Migrating+from+0.7+to+0.8">special tool</a> for migration. This migration can be done without downtime.