diff --git a/SDT/schema4.0/build.xml b/SDT/schema4.0/build.xml
index ca74f2f8baa22447c6c75c30b903c786887572d0..3f5101fb6f675867fbb0bac7a7bfa77314f574eb 100644
--- a/SDT/schema4.0/build.xml
+++ b/SDT/schema4.0/build.xml
@@ -92,7 +92,7 @@
     <schemavalidate warn="true">
       <fileset dir="${basedir}/test" includes="*.xml"/>
       <attribute name="http://apache.org/xml/features/xinclude" value="true"/>
-      <schema namespace="http://homegatewayinitiative.org/xml/dal/3.0"
+      <schema namespace="http://homegatewayinitiative.org/xml/dal/4.0"
 	      file="${path.src}/domain.xsd" />
       <schema namespace="http://www.w3.org/2001/XInclude"
 	      file="${basedir}/etc/XInclude.xsd" />
diff --git a/SDT/schema4.0/etc/dal.rnc b/SDT/schema4.0/etc/dal.rnc
index 728c734c43e4858e61cef9136e7e35a93ad60f8e..e9c05eee2933d959745c944234fcd9e9abdb851c 100644
--- a/SDT/schema4.0/etc/dal.rnc
+++ b/SDT/schema4.0/etc/dal.rnc
@@ -1,6 +1,6 @@
 
 namespace local = ""
-default namespace xsl = "http://homegatewayinitiative.org/xml/dal/3.0"
+default namespace xsl = "http://homegatewayinitiative.org/xml/dal/4.0"
 namespace xi = "http://www.w3.org/2001/XInclude"
 
 version = "1.0"
diff --git a/SDT/schema4.0/etc/domain.rnc b/SDT/schema4.0/etc/domain.rnc
index 1fdb1f2008cf338881a3df25d2d14ef1041c1ef5..6eb024fb5a76bffab2d2456135d70b125b641c55 100644
--- a/SDT/schema4.0/etc/domain.rnc
+++ b/SDT/schema4.0/etc/domain.rnc
@@ -65,12 +65,12 @@ BasicType =
   | "byte"
   | "float"
   | "array"
-  | "enum"
   | "date"
   | "time"
   | "datetime"
   | "blob"
   | "uri"
+  | "void"
 ConstraintsDef =
   element Constraints {
     element Constraint {
diff --git a/SDT/schema4.0/etc/schema.xmlns b/SDT/schema4.0/etc/schema.xmlns
index 4f691f5342ddd84d3301215f2286a9cd3887822d..d38050cfd3f90669fdcdad324f8f95609c56bf65 100644
--- a/SDT/schema4.0/etc/schema.xmlns
+++ b/SDT/schema4.0/etc/schema.xmlns
@@ -1,4 +1,4 @@
-targetNamespace="http://homegatewayinitiative.org/xml/dal/3.0" 
-	   xmlns="http://homegatewayinitiative.org/xml/dal/3.0" 
+targetNamespace="http://homegatewayinitiative.org/xml/dal/4.0" 
+	   xmlns="http://homegatewayinitiative.org/xml/dal/4.0" 
 	   xmlns:xs="http://www.w3.org/2001/XMLSchema" 
 	  
diff --git a/SDT/schema4.0/etc/schemas.xml b/SDT/schema4.0/etc/schemas.xml
index 3b0bea68871bb789a0a90378c2c425b777e77199..239fe56855cbe8beece56ae0739dae3ec4276b4e 100644
--- a/SDT/schema4.0/etc/schemas.xml
+++ b/SDT/schema4.0/etc/schemas.xml
@@ -1,6 +1,6 @@
 <locatingRules xmlns="http://thaiopensource.com/ns/locating-rules/1.0">
   
-  <namespace ns="http://homegatewayinitiative.org/xml/dal/2.0" typeId="DAL"/>
+  <namespace ns="http://homegatewayinitiative.org/xml/dal/4.0" typeId="DAL"/>
   <namespace ns="http://www.w3.org/2001/XInclude" typeId="XINC"/>
 
   <typeId id="DAL" uri="dal.rnc"/>
diff --git a/SDT/schema4.0/test/EchonetLiteExamples.xml b/SDT/schema4.0/test/EchonetLiteExamples.xml
index 76f7d8451fae82a4eada7a8cf527d7bc418c2042..429eaf89b5bd1622b56a31bd18c0d8d63befebf0 100644
--- a/SDT/schema4.0/test/EchonetLiteExamples.xml
+++ b/SDT/schema4.0/test/EchonetLiteExamples.xml
@@ -3,7 +3,7 @@
 <!-- Example SDT definition taken from EchonetLite https://github.com/ECHONET-Consortium -->
 
 
-<Domain xmlns="http://homegatewayinitiative.org/xml/dal/3.0"
+<Domain xmlns="http://homegatewayinitiative.org/xml/dal/4.0"
 	xmlns:xi="http://www.w3.org/2001/XInclude"
 	id="example.based.on.echonetLite">
 
@@ -119,19 +119,22 @@
 						<DataPoint name="door/CoverOpen/CloseStatus" readable="true" writable="false">
 							<Doc>This property indicates whether the door/cover is open or closed.</Doc>
 							<DataType>
-								<SimpleType type="enum" />
+								<!-- <SimpleType type="enum" /> -->
+								<SimpleType type="string" />
 							</DataType>
 						</DataPoint>
 						<DataPoint name="washingMachineSetting" readable="true" writable="true">
 							<Doc>Washing machine setting</Doc>
 							<DataType>
-								<SimpleType type="enum" />
+								<!-- <SimpleType type="enum" /> -->
+								<SimpleType type="string" />
 							</DataType>
 						</DataPoint>
 						<DataPoint name="currentStageOfWashingCycle" readable="true" writable="false">
 							<Doc>This property indicates the current stage of the washing cycle.</Doc>
 							<DataType>
-								<SimpleType type="enum" />
+								<!-- <SimpleType type="enum" /> -->
+								<SimpleType type="string" />
 							</DataType>
 						</DataPoint>
 						<DataPoint name="timeRemainingToCompleteWashingCycle" readable="true" writable="false">
@@ -149,7 +152,8 @@
 						<DataPoint name="onTimerReservationSetting" readable="true" writable="true">
 							<Doc>Reservation ON/OFF</Doc>
 							<DataType>
-								<SimpleType type="enum" />
+								<!-- <SimpleType type="enum" /> -->
+								<SimpleType type="boolean" />
 							</DataType>
 						</DataPoint>
 						<DataPoint name="onTimerSetting" readable="true" writable="true">
diff --git a/SDT/schema4.0/test/dal-core.xml b/SDT/schema4.0/test/dal-core.xml
index 65ec652d501ec799914a79bafa998b557b28791b..b1eec99fbedce40d2b6176193ccec8e21508a128 100644
--- a/SDT/schema4.0/test/dal-core.xml
+++ b/SDT/schema4.0/test/dal-core.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
 
-<Domain xmlns="http://homegatewayinitiative.org/xml/dal/3.0" 
+<Domain xmlns="http://homegatewayinitiative.org/xml/dal/4.0" 
 	id="hgi.dal.core">
 
 	<Modules>
diff --git a/SDT/schema4.0/test/dal-eg.xml b/SDT/schema4.0/test/dal-eg.xml
index 60a5b87029febb0e4fecadef0c8104741fb24517..f43718032fc38b361f476ccb624adc9791d5021e 100644
--- a/SDT/schema4.0/test/dal-eg.xml
+++ b/SDT/schema4.0/test/dal-eg.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
 
 <Domain xmlns:xi="http://www.w3.org/2001/XInclude"
-	xmlns="http://homegatewayinitiative.org/xml/dal/3.0" 
+	xmlns="http://homegatewayinitiative.org/xml/dal/4.0" 
 	id="com.telekom">
 
   <Imports>
diff --git a/SDT/schema4.0/test/example1.SDT.xml b/SDT/schema4.0/test/example1.SDT.xml
index fb922d8948fba620499300c4757d5c1ee404c147..eed2e371731128689fe137f6d629fd292d05041c 100644
--- a/SDT/schema4.0/test/example1.SDT.xml
+++ b/SDT/schema4.0/test/example1.SDT.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
 <!-- Example1 SDT inspired by some Echonet Lite examples -->
-<Domain xmlns="http://homegatewayinitiative.org/xml/dal/3.0"
+<Domain xmlns="http://homegatewayinitiative.org/xml/dal/4.0"
 	xmlns:xi="http://www.w3.org/2001/XInclude"
 	id="example1.SDT">
 
diff --git a/SDT/schema4.0/test/example2.SDT.xml b/SDT/schema4.0/test/example2.SDT.xml
index 82090f7174a241b2fe3f9912cc88dabb236af38e..2a9361a7016506c6bd40248969da25cb0b81692e 100644
--- a/SDT/schema4.0/test/example2.SDT.xml
+++ b/SDT/schema4.0/test/example2.SDT.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
 <!-- Example1 SDT inspired by some Echonet Lite examples -->
-<Domain xmlns="http://homegatewayinitiative.org/xml/dal/3.0"
+<Domain xmlns="http://homegatewayinitiative.org/xml/dal/4.0"
 	xmlns:xi="http://www.w3.org/2001/XInclude"
 	id="example2.SDT">
 
diff --git a/SDT/schema4.0/test/example3.SDT.xml b/SDT/schema4.0/test/example3.SDT.xml
index cb3c1836f61578cfb6103d9eae2e5a9183f61967..63da2490c4686afb54d85b795c17eb062d9ae7ef 100644
--- a/SDT/schema4.0/test/example3.SDT.xml
+++ b/SDT/schema4.0/test/example3.SDT.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
 <!-- Example1 SDT inspired by some Echonet Lite examples -->
-<Domain xmlns="http://homegatewayinitiative.org/xml/dal/3.0"
+<Domain xmlns="http://homegatewayinitiative.org/xml/dal/4.0"
 	xmlns:xi="http://www.w3.org/2001/XInclude"
 	id="example3.SDT">
 
diff --git a/SDT/schema4.0/test/mseeb.xml b/SDT/schema4.0/test/mseeb.xml
index 04dacf7655c7b11878c841b925df595adcf44ba8..4f5622f74b44ad1c389dd3623dfa6cbfb88d1475 100644
--- a/SDT/schema4.0/test/mseeb.xml
+++ b/SDT/schema4.0/test/mseeb.xml
@@ -62,7 +62,7 @@
 
 -->
 <Domain xmlns:xi="http://www.w3.org/2001/XInclude"
-    xmlns="http://homegatewayinitiative.org/xml/dal/3.0" 
+    xmlns="http://homegatewayinitiative.org/xml/dal/4.0" 
     id="org.homegatewayinitiative">
 
 <!-- The following import statements include ModuleClasses from HGI -->