diff --git a/src/user/Application.sol b/src/user/Application.sol
index fd70a3e..101a191 100644
--- a/src/user/Application.sol
+++ b/src/user/Application.sol
@@ -32,7 +32,7 @@ abstract contract Application is AppBase {
     }
 
     function ormpRecver() public view virtual override returns (address) {
-        return ORMP;
+        return _ORMP;
     }
 
     function _setAppConfig(address oracle, address relayer) internal virtual {
diff --git a/src/user/UpgradeableApplication.sol b/src/user/UpgradeableApplication.sol
index 33f06f8..995ebce 100644
--- a/src/user/UpgradeableApplication.sol
+++ b/src/user/UpgradeableApplication.sol
@@ -21,8 +21,8 @@ import "../interfaces/IORMP.sol";
 import "./AppBase.sol";
 
 abstract contract UpgradeableApplication is AppBase {
-    address private sender;
-    address private recver;
+    address private _sender;
+    address private _recver;
 
     event SetSender(address ormp);
     event SetRecver(address ormp);