In the latest builds are no longer entered the data for ticket 11373 "Notifications Purge old with cron" into the database after new installation. Thus is the configuration "Read Notification Expiration:" no longer possible.

Missing:
INSERT INTO phpbb_config (config_name, config_value) VALUES ('read_notification_expire_days', '30');
INSERT INTO phpbb_config (config_name, config_value) VALUES ('read_notification_last_gc', '0');
INSERT INTO phpbb_config (config_name, config_value) VALUES ('read_notification_gc', '86400');