diff --git a/Subscription/Subscription.sol b/Subscription/Subscription.sol
index 59cca71..0b45af2 100644
--- a/Subscription/Subscription.sol
+++ b/Subscription/Subscription.sol
@@ -33,6 +33,7 @@ contract Subscription {
 
     //who deploys the contract
     address public author;
+    uint8 public contractVersion;
 
     // the publisher may optionally deploy requirements for the subscription
     // so only meta transactions that match the requirements can be relayed
@@ -42,6 +43,7 @@ contract Subscription {
     uint256 public requiredPeriodSeconds;
     uint256 public requiredGasPrice;
 
+
     // similar to a nonce that avoids replay attacks this allows a single execution
     // every x seconds for a given subscription
     // subscriptionHash  => next valid block number
@@ -77,7 +79,8 @@ contract Subscription {
         address _tokenAddress,
         uint256 _tokenAmount,
         uint256 _periodSeconds,
-        uint256 _gasPrice
+        uint256 _gasPrice,
+        uint8 _version
     ) public {
         requiredToAddress=_toAddress;
         requiredTokenAddress=_tokenAddress;
@@ -85,6 +88,7 @@ contract Subscription {
         requiredPeriodSeconds=_periodSeconds;
         requiredGasPrice=_gasPrice;
         author=msg.sender;
+        contractVersion=_version;
     }
 
     // this is used by external smart contracts to verify on-chain that a
@@ -169,7 +173,7 @@ contract Subscription {
         uint256 nonce,// to allow multiple subscriptions with the same parameters
         bytes signature //proof the subscriber signed the meta trasaction
     )
-        external
+        public
         view
         returns (bool)
     {
@@ -242,8 +246,12 @@ contract Subscription {
         public
         returns (bool success)
     {
+        bytes32 subscriptionHash = getSubscriptionHash(
+            from, to, tokenAddress, tokenAmount, periodSeconds, gasPrice, nonce
+        );
+
         // make sure the subscription is valid and ready
-        require(isSubscriptionReady(from, to, tokenAddress, tokenAmount, periodSeconds, gasPrice, nonce, signature), "Subscription is not ready or conditions of transction are not met")
+        require( isSubscriptionReady(from, to, tokenAddress, tokenAmount, periodSeconds, gasPrice, nonce, signature), "Subscription is not ready or conditions of transction are not met" );
 
         //increment the timestamp by the period so it wont be valid until then
         nextValidTimestamp[subscriptionHash] = block.timestamp.add(periodSeconds);