优化设备状态保持，自动记录心跳间隔，三次心跳失败则设备离线，不在使用设备有效期字段作为唯一判断标准，提高容错能力和稳定性。

sql/update.sql

@@ -1,43 +1,3 @@
-alter table media_server
-    drop column streamNoneReaderDelayMS;
-
-alter table media_server
-    drop column sendRtpPortRange;
-
-alter table stream_proxy
-    add enable_disable_none_reader bit(1) default null;
-
+-- 2.6.6->2.6.7
 alter table device
-    add mediaServerId varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT 'auto';
-
-alter table device
-    add custom_name varchar(255) default null;
-
-alter table device
-    add sdpIp varchar(50) default null;
-
-alter table device
-    add localIp varchar(50) default null;
-
-alter table device
-    add password varchar(255) default null;
-
-alter table device
-    modify ip varchar(50) null;
-
-alter table device
-    modify port int null;
-
-alter table device
-    modify expires int null;
-
-alter table device
-    modify subscribeCycleForCatalog int null;
-
-alter table device
-    modify hostAddress varchar(50) null;
-
-alter table stream_proxy
-    change enable_hls enable_audio bit null;
-
-
+    add keepaliveIntervalTime int default null;