SSO SAML feature is available for both On-Premise Matomo and Cloud versions:
LoginSaml is a plugin for Matomo and is available for purchase on the Marketplace as a yearly subscription. While the subscription is active you will receive all updates for this plugin. The Users Flow plugin is released under the InnoCraft EULA.
If you use Matomo Cloud, you can get SSO via SAML by upgrading to the Matomo Cloud Enterprise plan. Please reach out to the team to get a quote or learn more.