Breaking: #81735 - Get rid of sysext:sv 

See forge#81735

Description 

The AuthenticationService has been moved into system extensios core. Class aliases are in place and will be removed with TYPO3 v10.

Impact 

The namespace of the classes AbstractAuthenticationService and AuthenticationService changed from \TYPO3\CMS\Sv to \TYPO3\CMS\Core\Authentication.

Affected Installations 

All instances, that use or extend the mentioned classes.

Migration 

Use the new namespaces as mentioned above.

More Information