diff --git a/docs/_jsdoc/tutorials/annotated-contract-metadata.md b/docs/_jsdoc/tutorials/annotated-contract-metadata.md
index d137a922..c1f2e235 100644
--- a/docs/_jsdoc/tutorials/annotated-contract-metadata.md
+++ b/docs/_jsdoc/tutorials/annotated-contract-metadata.md
@@ -255,4 +255,66 @@ This example is defining the concept of a person; who has a name, address and an
     }
   }
 }
-```
\ No newline at end of file
+```
+## String and Number validation
+
+Strict semantic checking can be performed on strings and numbers. As an example consider this extract of metadata describing the parameters of a function
+```
+  "parameters": [
+      {
+          "name": "pupilName",
+          "description": "",
+          "required": true,
+          "schema": {
+              "type": "string"
+          }
+      },
+      {
+          "name": "formId",
+          "description": "",
+          "required": true,
+          "schema": {
+              "type": "string",
+              "pattern": "^[a-zA-Z0-9]+$"
+          }
+      },
+      {
+          "name": "description",
+          "description": "",
+          "required": true,
+          "schema": {
+              "type": "string",
+              "maxLength": 100
+          }
+      },
+      {
+          "name": "lifetime",
+          "description": "days this is valid for (30 if not given)",
+          "required": false,
+          "schema": {
+              "type": "integer",
+              "minimum": 1,
+              "maximum": 30
+          }
+      },
+      {
+          "name": "startDate",
+          "description": "Start date yyyy-mm-dd, today if not specified",
+          "required": false,
+          "schema": {
+              "type": "string",
+              "format": "date"
+          }
+      }
+  ]
+```
+
+**Note: The `required` tag at present is not enforced by the node chaincode.**
+
+- __Pupilname__ this is a string, but has no restrictions placed up on it. 
+- __formId__ a string, but has to matched the regular expression. In this case it has to be exactly composed of lower or upcase letters and numbers
+- __description__ a string, with the restriction that it can't be more than 100 characters in length
+- __lifetime__ an integer with minimum value of 1 and maxiomum of 30
+- __startDate__ an string but has to contain a date (As defined by full-date - [RFC3339](http://xml2rfc.ietf.org/public/rfc/html/rfc3339.html#anchor14)).  
+
+The alternative to `format:date` is `format:dateTime` ... the string here has to confirmed to date-time defined in [RFC3339](http://xml2rfc.ietf.org/public/rfc/html/rfc3339.html#anchor14)
\ No newline at end of file
diff --git a/docs/_jsdoc/tutorials/tutorials.json b/docs/_jsdoc/tutorials/tutorials.json
index 4093e480..a4e43c6f 100644
--- a/docs/_jsdoc/tutorials/tutorials.json
+++ b/docs/_jsdoc/tutorials/tutorials.json
@@ -5,9 +5,6 @@
 	"using-contractinterface":{
 		"title":"Using the Contract Interface"
 	},
-	"using-iterators":{
-		"title":"Working with apis that return iterators"
-	},
 	"annotated-contract-metadata":{
 		"title":"Walkthrough of annotated metadata.json"
 	},
@@ -16,6 +13,12 @@
 	},
 	"using-typescript-decorators":{
 		"title":"Using TypeScript Decorators"
-	}
+	},
+	"data-types-and-contracts":{
+		"title":"Details of type handling"
+	},
+	"using-iterators": {
+        "title":"Working with apis that return iterators"
+    }
 
-}
+}
\ No newline at end of file
diff --git a/docs/_jsdoc/tutorials/using-iterators.md b/docs/_jsdoc/tutorials/using-iterators.md
index 066a457b..d739f39b 100644
--- a/docs/_jsdoc/tutorials/using-iterators.md
+++ b/docs/_jsdoc/tutorials/using-iterators.md
@@ -25,7 +25,7 @@ These apis are a request to return a set of data for which you need to iterate o
 
 These iterators were essentially asynchronous iterators (the next and close methods returned promises) but you couldn't use standard iterator capabilities such as for/of constructs in node because node could not work with the concept of asynchronous iterators.
 
-From fabric v2.x onwards, node chaincode will be using node 10 and this has added support for asynchronous iterators. Also in fabric v2.x onwards, fabric-shim has added support to enable it's asynchronous iterators so that `for/of` can now be used, but note that they don't have full support, so should not be used in generator functions.
+From fabric v2.x onwards, node chaincode will be using node 12 and this has added support for asynchronous iterators. Also in fabric v2.x onwards, fabric-shim has added support to enable it's asynchronous iterators so that `for/of` can now be used, but note that they don't have full support, so should not be used in generator functions.
 
 As a comparison, let's present first how you would use iterators in previous releases and then show the new way.