allations done with
the <code>--revision</code> flag. Upgrades of such installations will fail with an error.</div></aside></div><h2 id=upgrade-prerequisites>Upgrade prerequisites</h2><p>Before you begin the upgrade process, check the following prerequisites:</p><ul><li><p>The installed Istio version is no more than one minor version less than the upgrade version.
For example, 1.6.0 or higher is required before you start the upgrade process to 1.7.x.</p></li><li><p>Your Istio installation was <a href=/v1.17