diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index e69de29bb..3743ad53e 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -0,0 +1,5 @@
+Validator:
+* check StructureDefinition derivation consistency
+
+Other code changes:
+* Add support for new FHIR releases
\ No newline at end of file
diff --git a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/i18n/I18nConstants.java b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/i18n/I18nConstants.java
index 1a67ff30d..5deaf2ba9 100644
--- a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/i18n/I18nConstants.java
+++ b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/i18n/I18nConstants.java
@@ -361,6 +361,7 @@ public class I18nConstants {
   public static final String SD_MUST_HAVE_DERIVATION = "SD_MUST_HAVE_DERIVATION";
   public static final String SD_NESTED_MUST_SUPPORT_DIFF = "SD_NESTED_MUST_SUPPORT_DIFF";
   public static final String SD_NESTED_MUST_SUPPORT_SNAPSHOT = "SD_NESTED_MUST_SUPPORT_SNAPSHOT";
+  public static final String SD_DERIVATION_KIND_MISMATCH = "SD_DERIVATION_KIND_MISMATCH";
   public static final String SD_ED_TYPE_PROFILE_UNKNOWN = "SD_ED_TYPE_PROFILE_UNKNOWN";
   public static final String SD_ED_TYPE_PROFILE_NOTYPE = "SD_ED_TYPE_PROFILE_NOTYPE";
   public static final String SD_ED_TYPE_PROFILE_WRONG = "SD_ED_TYPE_PROFILE_WRONG";
diff --git a/org.hl7.fhir.utilities/src/main/resources/Messages.properties b/org.hl7.fhir.utilities/src/main/resources/Messages.properties
index bf567fc41..0d5935dcb 100644
--- a/org.hl7.fhir.utilities/src/main/resources/Messages.properties
+++ b/org.hl7.fhir.utilities/src/main/resources/Messages.properties
@@ -701,4 +701,4 @@ TYPE_SPECIFIC_CHECKS_DT_QTY_MAX_VALUE_WRONG = The value in the instance ({2}) is
 TYPE_SPECIFIC_CHECKS_DT_QTY_MAX_VALUE_WRONG_UCUM = The value in the instance ({0} {1}) is greater than the specified maxValue ({2} {3}) after UCUM conversion 
 TYPE_SPECIFIC_CHECKS_DT_BASE64_NO_WS_ERROR = Base64 encoded values are not allowed to contain any whitespace (per RFC 4648). Note that non-validating readers are encouraged to accept whitespace anyway
 TYPE_SPECIFIC_CHECKS_DT_BASE64_NO_WS_WARNING = Base64 encoded values SHOULD not contain any whitespace (per RFC 4648). Note that non-validating readers are encouraged to accept whitespace anyway
-
+SD_DERIVATION_KIND_MISMATCH = The structure definition constrains a kind of {0}, but has a different kind ({1})
diff --git a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/InstanceValidator.java b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/InstanceValidator.java
index a2b3820d9..416219e29 100644
--- a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/InstanceValidator.java
+++ b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/InstanceValidator.java
@@ -1312,7 +1312,7 @@ public class InstanceValidator extends BaseValidator implements IResourceValidat
     String system = c.getSystem();
     String display = c.getDisplay();
     String version = c.getVersion();
-    rule(errors, IssueType.CODEINVALID, element.line(), element.col(), path, isAbsolute(system), I18nConstants.TERMINOLOGY_TX_SYSTEM_RELATIVE);
+    rule(errors, IssueType.CODEINVALID, element.line(), element.col(), path, isCodeSystemReferenceValid(system), I18nConstants.TERMINOLOGY_TX_SYSTEM_RELATIVE);
 
     if (system != null && code != null && !noTerminologyChecks) {
       rule(errors, IssueType.CODEINVALID, element.line(), element.col(), path, !isValueSet(system), I18nConstants.TERMINOLOGY_TX_SYSTEM_VALUESET2, system);
@@ -1568,7 +1568,7 @@ public class InstanceValidator extends BaseValidator implements IResourceValidat
 
   private void checkCodedElement(List<ValidationMessage> errors, String path, Element element, StructureDefinition profile, ElementDefinition theElementCntext, boolean inCodeableConcept, boolean checkDisplay, NodeStack stack,
       String theCode, String theSystem, String theVersion, String theDisplay) {
-    rule(errors, IssueType.CODEINVALID, element.line(), element.col(), path, isAbsolute(theSystem), I18nConstants.TERMINOLOGY_TX_SYSTEM_RELATIVE);
+    rule(errors, IssueType.CODEINVALID, element.line(), element.col(), path, isCodeSystemReferenceValid(theSystem), I18nConstants.TERMINOLOGY_TX_SYSTEM_RELATIVE);
     warning(errors, IssueType.CODEINVALID, element.line(), element.col(), path, Utilities.noString(theCode) || !Utilities.noString(theSystem), I18nConstants.TERMINOLOGY_TX_SYSTEM_NO_CODE);
 
     if (theSystem != null && theCode != null && !noTerminologyChecks) {
@@ -2023,7 +2023,7 @@ public class InstanceValidator extends BaseValidator implements IResourceValidat
 
   private void checkIdentifier(List<ValidationMessage> errors, String path, Element element, ElementDefinition context) {
     String system = element.getNamedChildValue("system");
-    rule(errors, IssueType.CODEINVALID, element.line(), element.col(), path, isAbsolute(system), I18nConstants.TYPE_SPECIFIC_CHECKS_DT_IDENTIFIER_SYSTEM);
+    rule(errors, IssueType.CODEINVALID, element.line(), element.col(), path, isIdentifierSystemReferenceValid(system), I18nConstants.TYPE_SPECIFIC_CHECKS_DT_IDENTIFIER_SYSTEM);
     if ("urn:ietf:rfc:3986".equals(system)) {
       String value = element.getNamedChildValue("value");
       rule(errors, IssueType.CODEINVALID, element.line(), element.col(), path, isAbsolute(value), I18nConstants.TYPE_SPECIFIC_CHECKS_DT_IDENTIFIER_IETF_SYSTEM_VALUE); 
@@ -3488,13 +3488,20 @@ public class InstanceValidator extends BaseValidator implements IResourceValidat
     return fmt.length() > 10 && (fmt.substring(10).contains("-") || fmt.substring(10).contains("+") || fmt.substring(10).contains("Z"));
   }
 
-  private boolean isAbsolute(String uri) {
-    return Utilities.noString(uri) || uri.startsWith("http:") || uri.startsWith("https:") || uri.startsWith("urn:uuid:") || uri.startsWith("urn:oid:") || uri.startsWith("urn:ietf:")
-      || uri.startsWith("urn:iso:") || uri.startsWith("urn:iso-astm:") || uri.startsWith("mailto:")|| isValidFHIRUrn(uri);
+  private boolean isAbsolute(String uri, String... protocols) {
+    return Utilities.noString(uri) || uri.startsWith("http:") || uri.startsWith("https:") || uri.startsWith("urn:");
   }
 
-  private boolean isValidFHIRUrn(String uri) {
-    return (uri.equals("urn:x-fhir:uk:id:nhs-number")) || uri.startsWith("urn:"); // Anyone can invent a URN, so why should we complain?
+  private boolean isCodeSystemReferenceValid(String uri) {
+    return isSystemReferenceValid(uri);    
+  }
+
+  private boolean isIdentifierSystemReferenceValid(String uri) {
+    return isSystemReferenceValid(uri) || uri.startsWith("ldap:");
+  }
+
+  private boolean isSystemReferenceValid(String uri) {
+    return uri.startsWith("http:") || uri.startsWith("https:") || uri.startsWith("urn:");
   }
 
   public boolean isAnyExtensionsAllowed() {
diff --git a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/type/StructureDefinitionValidator.java b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/type/StructureDefinitionValidator.java
index 3164ba886..de19f58f9 100644
--- a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/type/StructureDefinitionValidator.java
+++ b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/type/StructureDefinitionValidator.java
@@ -97,6 +97,8 @@ public class StructureDefinitionValidator extends BaseValidator {
             }
           }
         }
+        rule(errors, IssueType.NOTFOUND, stack.getLiteralPath(), base.getKindElement().primitiveValue().equals(src.getChildValue("kind")), 
+            I18nConstants.SD_DERIVATION_KIND_MISMATCH, base.getKindElement().primitiveValue(), src.getChildValue("kind"));
       }
     } catch (FHIRException | IOException e) {
       rule(errors, IssueType.EXCEPTION, stack.getLiteralPath(), false, I18nConstants.ERROR_GENERATING_SNAPSHOT, e.getMessage());