old_contents: from addons.base.serializer import CitationsAddonSerializer
  
  class ZoteroSerializer(CitationsAddonSerializer):
      addon_short_name = 'zotero'
  
      @property
      def serialized_node_settings(self):
          result = super(ZoteroSerializer, self).serialized_node_settings
          result['library'] = {
              'name': self.node_settings.fetch_library_name
          }
          return result
  
new_contents: from addons.base.serializer import CitationsAddonSerializer
  
  class ZoteroSerializer(CitationsAddonSerializer):
      addon_short_name = 'zotero'
  
      @property
      def serialized_node_settings(self):
          result = super(ZoteroSerializer, self).serialized_node_settings
          result['library'] = {
              'name': self.node_settings.fetch_library_name
          }
          result['groups'] = self.node_settings.fetch_groups
          return result
  
subject: Add groups key in response to zotero/settings.