Merge pull request #1297 from kherge/1.7

Removing conflicting validation rule.

Author: xabbuh

DependencyInjection/Configuration.php

@@ -106,10 +106,6 @@ public function getConfigTreeBuilder()
                     ->end()
                 ->end()
                 ->arrayNode('serializer')
-                    ->validate()
-                        ->ifTrue(function ($v) { return !empty($v['version']) && !empty($v['groups']); })
-                        ->thenInvalid('Only either a version or a groups exclusion strategy can be set')
-                    ->end()
                     ->addDefaultsIfNotSet()
                     ->children()
                         ->scalarNode('version')->defaultNull()->end()