diff --git a/src/oauth2server/Server.php b/src/oauth2server/Server.php
index 6737d431..415d5cb8 100644
--- a/src/oauth2server/Server.php
+++ b/src/oauth2server/Server.php
@@ -22,10 +22,6 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 namespace oauth2server;
 
-use oauth2server\OAuth2ServerDatabase;
-
-abstract class ServerDB implements OAuth2ServerDatabase {}
-
 class OAuthServerClientException extends \Exception {}
 
 class OAuthServerUserException extends \Exception {}