diff --git a/scl-extension/src/main/resources/xsd/SCL_CoMPAS.xsd b/scl-extension/src/main/resources/xsd/SCL_CoMPAS.xsd
index eaf1343..85b781b 100644
--- a/scl-extension/src/main/resources/xsd/SCL_CoMPAS.xsd
+++ b/scl-extension/src/main/resources/xsd/SCL_CoMPAS.xsd
@@ -15,6 +15,7 @@ SPDX-License-Identifier: Apache-2.0
             Version 1.1 Release 2022/01/21
             Version 1.2 Release 2022/06/08
             Version 1.3 Release 2022/09/08
+            Version 1.4 Release 2023/02/28
         </xs:documentation>
     </xs:annotation>
 
@@ -100,36 +101,36 @@ SPDX-License-Identifier: Apache-2.0
         </xs:sequence>
     </xs:complexType>
 
- <xs:simpleType name="tCompasIEDType">
+    <xs:simpleType name="tCompasIEDType">
         <xs:annotation>
             <xs:documentation xml:lang="en">
                 IED type to be used to identity the set of LDevice.inst handled by the IED
             </xs:documentation>
         </xs:annotation>
         <xs:restriction base="xs:string">
-           <xs:enumeration value="SCU"/>
-           <xs:enumeration value="SCU-MCB"/>
-           <xs:enumeration value="SCU-TG"/>
-           <xs:enumeration value="SCU-ORG"/>
-           <xs:enumeration value="BCU"/>
-           <xs:enumeration value="BCU-LIGNE"/>
-           <xs:enumeration value="BCU-CBO"/>
-           <xs:enumeration value="BPU"/>
-           <xs:enumeration value="MU"/>
-           <xs:enumeration value="SAMU"/>
-           <xs:enumeration value="PROT"/>
-           <xs:enumeration value="TAC"/>
-           <xs:enumeration value="PX"/>
-           <xs:enumeration value="PDIS"/>
-           <xs:enumeration value="PDB"/>
-           <xs:enumeration value="AUT"/>
-           <xs:enumeration value="PDIF"/>
-           <xs:enumeration value="GRP"/>
-           <xs:enumeration value="GW"/>
-           <xs:enumeration value="TG"/>
-           <xs:enumeration value="TOPO"/>
-           <xs:enumeration value="ADEFINIR"/>
-           <xs:enumeration value="IEDTEST"/>
+            <xs:enumeration value="SCU"/>
+            <xs:enumeration value="SCU-MCB"/>
+            <xs:enumeration value="SCU-TG"/>
+            <xs:enumeration value="SCU-ORG"/>
+            <xs:enumeration value="BCU"/>
+            <xs:enumeration value="BCU-LIGNE"/>
+            <xs:enumeration value="BCU-CBO"/>
+            <xs:enumeration value="BPU"/>
+            <xs:enumeration value="MU"/>
+            <xs:enumeration value="SAMU"/>
+            <xs:enumeration value="PROT"/>
+            <xs:enumeration value="TAC"/>
+            <xs:enumeration value="PX"/>
+            <xs:enumeration value="PDIS"/>
+            <xs:enumeration value="PDB"/>
+            <xs:enumeration value="AUT"/>
+            <xs:enumeration value="PDIF"/>
+            <xs:enumeration value="GRP"/>
+            <xs:enumeration value="GW"/>
+            <xs:enumeration value="TG"/>
+            <xs:enumeration value="TOPO"/>
+            <xs:enumeration value="ADEFINIR"/>
+            <xs:enumeration value="IEDTEST"/>
         </xs:restriction>
     </xs:simpleType>
 
@@ -194,6 +195,7 @@ SPDX-License-Identifier: Apache-2.0
         <xs:restriction base="xs:string">
             <xs:enumeration value="Up"/>
             <xs:enumeration value="Down"/>
+            <xs:enumeration value="N/A"/>
         </xs:restriction>
     </xs:simpleType>
 
@@ -238,13 +240,19 @@ SPDX-License-Identifier: Apache-2.0
     <xs:complexType name="tCompasICDHeader" mixed="true">
         <xs:annotation>
             <xs:documentation xml:lang="en">
-                Define specific Compas attributes to identify uniquely one ICD file with-in a SystemVersion for a given IEDredundancy. The UUID of this combinaison is defined by the ICDSystemVersionUUID.
+                Define specific Compas attributes to identify uniquely one IED with-in a SystemVersion for a given ICD, IEDredundancy, IEDSystemVersionInstance
+                The IEDType defines the set of LD which are supported by the hardware
+                The VendorName, IEDmodel, hwRev, swRev, headerId, headerVersion, headerRevision are issued from the ICD file
+                The UUID of this combination is defined by the ICDSystemVersionUUID.
                 This private is intended to be used in the STD file (/IED level) and SSD (/LNode level)
+                At LNode level it defines the link between the Function, the associated LD, LN and the implementation in a given IED
+                At IED level, it defines the link of the IED within the SystemVersion
             </xs:documentation>
         </xs:annotation>
         <xs:attribute name="ICDSystemVersionUUID" type="xs:string" use="optional"/>
         <xs:attribute name="IEDType" type="tCompasIEDType" use="required"/>
-        <xs:attribute name="IEDinstance" type="xs:string" use="optional"/>
+        <xs:attribute name="IEDSubstationinstance" type="xs:integer" use="optional"/>
+        <xs:attribute name="IEDSystemVersioninstance" type="xs:integer" use="optional"/>
         <xs:attribute name="IEDName" type="xs:string" use="optional"/>
         <xs:attribute name="VendorName" type="xs:string" use="required"/>
         <xs:attribute name="IEDmodel" type="xs:string" use="required"/>
@@ -261,6 +269,8 @@ SPDX-License-Identifier: Apache-2.0
         <xs:annotation>
             <xs:documentation xml:lang="en">
                 Identify the SystemVersion to which the functional Bay and IED belongs to. This Private can be used in /Bay in substation and in the /IED.
+                The MainSystemVersion refers to a set of functional requirements and functions
+                The MinorSystemVersion is linked to a given bayKind and defines uniquely the set of ICD which are qualified
             </xs:documentation>
         </xs:annotation>
         <xs:attribute name="MainSystemVersion" type="xs:string" use="optional"/>
@@ -298,21 +308,20 @@ SPDX-License-Identifier: Apache-2.0
     </xs:complexType>
 
     <xs:complexType name="tCompasTopo">
-      <xs:annotation>
-        <xs:documentation xml:lang="en">
-            Describe the connectivity node and layout order for a given Bay;can be multiple instanciated in case of bay which is connected to multiple nodes
-        </xs:documentation>
-      </xs:annotation>
-      <xs:attribute name="Node" type="xs:string" use="required"/>
-      <xs:attribute name="NodeOrder" type="xs:integer" use="required"/>
-      <xs:attribute name="BusBarSectionOrder" type="xs:integer" use="optional"/>
-      <xs:attribute name="Direction" type="tCompasTopoNodeDirection" use="required"/>
+        <xs:annotation>
+            <xs:documentation xml:lang="en">
+                Describe the connectivity node and layout order for a given Bay;can be multiple instanciated in case of bay which is connected to multiple nodes
+            </xs:documentation>
+        </xs:annotation>
+        <xs:attribute name="Node" type="xs:string" use="required"/>
+        <xs:attribute name="NodeOrder" type="xs:integer" use="required"/>
+        <xs:attribute name="BusBarSectionOrder" type="xs:integer" use="optional"/>
+        <xs:attribute name="Direction" type="tCompasTopoNodeDirection" use="required"/>
     </xs:complexType>
 
     <xs:element name="SclName" type="tCompasSclName"/>
     <xs:element name="SclFileType" type="tCompasSclFileType"/>
     <xs:element name="Labels" type="tCompasLabels"/>
-    
     <xs:element name="Flow" type="tCompasFlow"/>
     <xs:element name="Bay" type="tCompasBay"/>
     <xs:element name="LDevice" type="tCompasLDevice"/>