1. Replaced all "xsd:IDREF" with "xsd:string" to remove the assumption that all referenced elements must reside in the same XML file. This allows us to import a method plug-in that references elements in the method library.

2. Removed redundant <xsd:element> definitions such as <xsd:element name="Discipline" type="uma:Discipline"> and <xsd:element name="MethodPackage" type="uma:MethodPackage">.

We only need the <xsd:complexType> definition for most elements. After the cleanup, we are left with 3 root-level <xsd:element> definitions:

	<xsd:complexType name="MethodPlugin">
	<xsd:complexType name="MethodConfiguration">
	<xsd:complexType name="MethodLibrary">

This implies that the XML file can have <MethodPlugin>, <MethodConfiguration> or <MethodLibrary> as the root element. This gives us the flexibility of exporting a single method plug-in, a single method configuration or a method library with 2 or more method plug-ins and configurations.

3. Added <xsd:element name="Whitepaper" type="xsd:string"/> to ContentElement and Activity. For example,

	<xsd:complexType name="ContentElement">
		<xsd:complexContent>
			<xsd:extension base="uma:DescribableElement">
				<xsd:sequence>
					<xsd:choice minOccurs="0" maxOccurs="unbounded">
						<xsd:element name="Checklist" type="xsd:string"/>
						<xsd:element name="Concept" type="xsd:string"/>
						<xsd:element name="Example" type="xsd:string"/>
						<xsd:element name="Guideline" type="xsd:string"/>
						<xsd:element name="ReusableAsset" type="xsd:string"/>
						<xsd:element name="SupportingMaterial" type="xsd:string"/>
						<xsd:element name="Whitepaper" type="xsd:string"/>
					</xsd:choice>
				</xsd:sequence>
				<xsd:attribute name="variabilityType" type="uma:VariabilityType"/>
				<xsd:attribute name="variabilityBasedOnElement" type="xsd:string"/>
			</xsd:extension>
		</xsd:complexContent>
	</xsd:complexType>

4. Removed VariabilityElement and updated the Section, ContentElement and Activity definition with the "variabilityType" and "variabilityBasedOnElement" attributes. For example,

	<xsd:complexType name="ContentElement">
		<xsd:complexContent>
			<xsd:extension base="uma:DescribableElement">
				<xsd:sequence>
					<xsd:choice minOccurs="0" maxOccurs="unbounded">
						<xsd:element name="Checklist" type="xsd:string"/>
						<xsd:element name="Concept" type="xsd:string"/>
						<xsd:element name="Example" type="xsd:string"/>
						<xsd:element name="Guideline" type="xsd:string"/>
						<xsd:element name="ReusableAsset" type="xsd:string"/>
						<xsd:element name="SupportingMaterial" type="xsd:string"/>
						<xsd:element name="Whitepaper" type="xsd:string"/>
					</xsd:choice>
				</xsd:sequence>
				<xsd:attribute name="variabilityType" type="uma:VariabilityType"/>
				<xsd:attribute name="variabilityBasedOnElement" type="xsd:string"/>
			</xsd:extension>
		</xsd:complexContent>
	</xsd:complexType>

If  "Role 1" extends "Role 2", the XML definition will now be:

	<ContentElement xsi:type="uma:Role" id="role_1" name="Role 1"/>
	<ContentElement xsi:type="uma:Role" id="role_2" name="Role 2" variabilityType="extends" variabilityBasedOnElement="role_1" />	

5. Updated the ProcessComponent defintion. The "Process" child element type should be "uma:Process" not "xsd:IDREF" or "xsd:string".

	<xsd:complexType name="ProcessComponent">
		<xsd:complexContent>
			<xsd:extension base="uma:ProcessPackage">
				<xsd:sequence>
					<xsd:element name="Copyright" type="xsd:string" minOccurs="0"/>
					<xsd:element name="Interface" type="uma:ProcessComponentInterface" minOccurs="0"/>
					<xsd:element name="Process" type="uma:Process" minOccurs="1"/>
				</xsd:sequence>
				<xsd:attribute name="authors" type="xsd:string">
					<xsd:annotation>
						<xsd:documentation>Every Method Unit is being created and owned by an author or authoring team.</xsd:documentation>
					</xsd:annotation>
				</xsd:attribute>
				<xsd:attribute name="changeDate" type="xsd:date">
					<xsd:annotation>
						<xsd:documentation>The date the last change that resulted into this version has been made.</xsd:documentation>
					</xsd:annotation>
				</xsd:attribute>
				<xsd:attribute name="changeDescription" type="xsd:string">
					<xsd:annotation>
						<xsd:documentation>The description of the last change that resulted into this version.</xsd:documentation>
					</xsd:annotation>
				</xsd:attribute>
				<xsd:attribute name="version" type="xsd:string">
					<xsd:annotation>
						<xsd:documentation>Every Package has a version number used to track changes.</xsd:documentation>
					</xsd:annotation>
				</xsd:attribute>
			</xsd:extension>
		</xsd:complexContent>
	</xsd:complexType>

6. Added "CategoryContentPackage" to simply the definition of standard and custom categories. A 'CategoryContentPackage" can only contain ContentCategory elements. The XML Schema definition is:

	<xsd:complexType name="ContentCategoryPackage">
		<xsd:annotation>
			<xsd:documentation>A special Method Package that only contains Content Category Elements.</xsd:documentation>
		</xsd:annotation>
		<xsd:complexContent>
			<xsd:extension base="uma:MethodPackage">
				<xsd:choice minOccurs="0" maxOccurs="unbounded">
					<xsd:element name="ContentCategory" type="uma:ContentCategory"/>
				</xsd:choice>
			</xsd:extension>
		</xsd:complexContent>
	</xsd:complexType>

An example would be:

	<MethodPackage xsi:type="uma:ContentCategoryPackage">
		<ContentCategory xsi:type="uma:RoleSet" id="role_set_1" name="Role Set 1">
			<Role>role_1</Role>
		</ContentCategory>
		<ContentCategory xsi:type="uma:RoleSet" id="role_set_2" name="Role Set 2">
			<Role>role_2</Role>
		</ContentCategory>
		<ContentCategory xsi:type="uma:RoleSetGrouping" id="role_set_grouping_1" name="Role Set Grouping 1">
			<RoleSet>role_set_1</RoleSet>
			<RoleSet>role_set_2</RoleSet>
		</ContentCategory>
		<ContentCategory xsi:type="uma:CustomCategory" id="custom_category_1" name="Custom Category 1">
			<SubCategory>custom_category_2</SubCategory>
		</ContentCategory>
		<ContentCategory xsi:type="uma:CustomCategory" id="custom_category_2" name="Custom Category 2">
			<CategorizedElement>role_set_1</CategorizedElement>
			<CategorizedElement>role_set_2</CategorizedElement>			
		</ContentCategory>
	</MethodPackage>	

7. Updated the <xsd:complexType name="MethodElement"> definition. Its "id" attribute type has been changed frrom "xsd:ID" to "xsd:string".

8. Replaced all <xsd:date> with <xsd:dateTime> to include time and timezone information. See http://books.xmlschemata.org/relaxng/ch19-77049.html or http://www.w3schools.com/schema/schema_dtypes_date.asp for more information.