diff --git a/contracts/helper/CloneFactory.sol b/contracts/helper/CloneFactory.sol
index 0476913..fd8f755 100644
--- a/contracts/helper/CloneFactory.sol
+++ b/contracts/helper/CloneFactory.sol
@@ -12,6 +12,9 @@ interface ICloneFactory {
     function clone(address prototype) external returns (address proxy);
 }
 
+// introduction of proxy mode design: https://docs.openzeppelin.com/upgrades/2.8/
+// minimum implementation of transparent proxy: https://eips.ethereum.org/EIPS/eip-1167
+
 contract CloneFactory is ICloneFactory {
     function clone(address prototype) external override returns (address proxy) {
         bytes20 targetBytes = bytes20(prototype);
diff --git a/contracts/impl/Storage.sol b/contracts/impl/Storage.sol
index f805dc1..dd34d3e 100644
--- a/contracts/impl/Storage.sol
+++ b/contracts/impl/Storage.sol
@@ -106,6 +106,6 @@ contract Storage is InitializableOwnable, ReentrancyGuard {
 
     // ============ Version Control ============
     function version() external pure returns (uint256) {
-        return 1;
+        return 100; // 1.0.0
     }
 }