diff --git a/contracts/deploy/Factory.sol b/contracts/deploy/Factory.sol
new file mode 100644
index 0000000..f63bf71
--- /dev/null
+++ b/contracts/deploy/Factory.sol
@@ -0,0 +1,57 @@
+pragma solidity ^0.4.17;
+
+import "../common/Controlled.sol";
+
+contract Factory is Controlled {
+
+    event NewKernel(address newKernel, bytes infohash);
+
+    struct Version {
+        uint256 blockNumber;
+        uint256 timestamp;
+        address kernel;
+        bytes infohash;
+    }
+    mapping (address => uint256) versionMap;
+
+    Version[] versionLog;
+    uint256 latestUpdate;
+    address latestKernel;
+
+    function Factory(address _kernel, bytes _infohash)
+        public 
+    {
+        _setKernel(_kernel, _infohash);
+    }
+
+    function setKernel(address _kernel, bytes _infohash)
+        external 
+        onlyController
+    {
+        _setKernel(_kernel, _infohash);
+    }
+
+    function getVersion(uint256 index) public view
+        returns(uint256 blockNumber,
+                uint256 timestamp,
+                address kernel,
+                bytes infohash)
+    {
+        return (versionLog[index].blockNumber, 
+                versionLog[index].timestamp, 
+                versionLog[index].kernel, 
+                versionLog[index].infohash);
+    }
+
+    function _setKernel(address _kernel, bytes _infohash) 
+        internal
+    {
+        require(_kernel != latestKernel);
+        versionMap[_kernel] = versionLog.length;
+        versionLog.push(Version({blockNumber: block.number, timestamp: block.timestamp, kernel: _kernel, infohash: _infohash}));
+        latestUpdate = block.timestamp;
+        latestKernel = _kernel;
+        NewKernel(_kernel, _infohash);
+    }
+
+}
\ No newline at end of file
diff --git a/contracts/deploy/UpdatableInstance.sol b/contracts/deploy/UpdatableInstance.sol
index 550df8d..60f6d0a 100644
--- a/contracts/deploy/UpdatableInstance.sol
+++ b/contracts/deploy/UpdatableInstance.sol
@@ -10,6 +10,8 @@ import "./Instance.sol";
  */
 contract UpdatableInstance is Instance {
 
+    event InstanceUpdated(address oldKernel, address newKernel);
+
     function UpdatableInstance(address _kernel) 
         Instance(_kernel) 
         public
@@ -19,6 +21,7 @@ contract UpdatableInstance is Instance {
     
     function updateUpdatableInstance(address _kernel) external {
         require(msg.sender == address(this));
+        InstanceUpdated(kernel, _kernel);
         kernel = _kernel;
     }