diff --git a/org.hl7.fhir.convertors/pom.xml b/org.hl7.fhir.convertors/pom.xml
index 4e468c855..d031b4f44 100644
--- a/org.hl7.fhir.convertors/pom.xml
+++ b/org.hl7.fhir.convertors/pom.xml
@@ -5,7 +5,7 @@
     <parent>
         <groupId>ca.uhn.hapi.fhir</groupId>
         <artifactId>org.hl7.fhir.core</artifactId>
-        <version>6.3.18-SNAPSHOT</version>
+        <version>6.3.19-SNAPSHOT</version>
         <relativePath>../pom.xml</relativePath>
     </parent>
 
diff --git a/org.hl7.fhir.dstu2/pom.xml b/org.hl7.fhir.dstu2/pom.xml
index e150e70c4..1bd39e603 100644
--- a/org.hl7.fhir.dstu2/pom.xml
+++ b/org.hl7.fhir.dstu2/pom.xml
@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>ca.uhn.hapi.fhir</groupId>
 		<artifactId>org.hl7.fhir.core</artifactId>
-		<version>6.3.18-SNAPSHOT</version>
+		<version>6.3.19-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/org.hl7.fhir.dstu2016may/pom.xml b/org.hl7.fhir.dstu2016may/pom.xml
index 0ece8835b..241e03fd2 100644
--- a/org.hl7.fhir.dstu2016may/pom.xml
+++ b/org.hl7.fhir.dstu2016may/pom.xml
@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>ca.uhn.hapi.fhir</groupId>
 		<artifactId>org.hl7.fhir.core</artifactId>
-		<version>6.3.18-SNAPSHOT</version>
+		<version>6.3.19-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/org.hl7.fhir.dstu3/pom.xml b/org.hl7.fhir.dstu3/pom.xml
index 92ca90f77..fa5bd7bb0 100644
--- a/org.hl7.fhir.dstu3/pom.xml
+++ b/org.hl7.fhir.dstu3/pom.xml
@@ -5,7 +5,7 @@
     <parent>
         <groupId>ca.uhn.hapi.fhir</groupId>
         <artifactId>org.hl7.fhir.core</artifactId>
-        <version>6.3.18-SNAPSHOT</version>
+        <version>6.3.19-SNAPSHOT</version>
         <relativePath>../pom.xml</relativePath>
     </parent>
 
diff --git a/org.hl7.fhir.r4/pom.xml b/org.hl7.fhir.r4/pom.xml
index 03c7bc1c6..4372e2f8f 100644
--- a/org.hl7.fhir.r4/pom.xml
+++ b/org.hl7.fhir.r4/pom.xml
@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>ca.uhn.hapi.fhir</groupId>
 		<artifactId>org.hl7.fhir.core</artifactId>
-		<version>6.3.18-SNAPSHOT</version>
+		<version>6.3.19-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/model/NamingSystem.java b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/model/NamingSystem.java
index ce5c67af6..5313ee7a2 100644
--- a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/model/NamingSystem.java
+++ b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/model/NamingSystem.java
@@ -347,6 +347,8 @@ public class NamingSystem extends MetadataResource {
     }
 
     public String toCode(NamingSystemIdentifierType code) {
+      if (code == NamingSystemIdentifierType.NULL)
+        return null;
       if (code == NamingSystemIdentifierType.OID)
         return "oid";
       if (code == NamingSystemIdentifierType.UUID)
diff --git a/org.hl7.fhir.r4b/pom.xml b/org.hl7.fhir.r4b/pom.xml
index 6eb9b978b..c8e0256d1 100644
--- a/org.hl7.fhir.r4b/pom.xml
+++ b/org.hl7.fhir.r4b/pom.xml
@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>ca.uhn.hapi.fhir</groupId>
 		<artifactId>org.hl7.fhir.core</artifactId>
-		<version>6.3.18-SNAPSHOT</version>
+		<version>6.3.19-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/org.hl7.fhir.r5/pom.xml b/org.hl7.fhir.r5/pom.xml
index 986926024..96ce86cd1 100644
--- a/org.hl7.fhir.r5/pom.xml
+++ b/org.hl7.fhir.r5/pom.xml
@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>ca.uhn.hapi.fhir</groupId>
 		<artifactId>org.hl7.fhir.core</artifactId>
-		<version>6.3.18-SNAPSHOT</version>
+		<version>6.3.19-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/model/NamingSystem.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/model/NamingSystem.java
index 6639afdd5..80aec8825 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/model/NamingSystem.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/model/NamingSystem.java
@@ -312,6 +312,8 @@ public class NamingSystem extends MetadataResource {
         throw new FHIRException("Unknown NamingSystemType code '"+codeString+"'");
         }
     public String toCode(NamingSystemType code) {
+      if (code == NamingSystemType.NULL)
+        return null;
       if (code == NamingSystemType.CODESYSTEM)
         return "codesystem";
       if (code == NamingSystemType.IDENTIFIER)
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/DataRenderer.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/DataRenderer.java
index 67b07b861..1bd6e7572 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/DataRenderer.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/DataRenderer.java
@@ -278,10 +278,11 @@ public class DataRenderer extends Renderer implements CodeResolver {
     String s = codeSystem+'-'+code; 
     StringBuilder b = new StringBuilder(); 
     for (char c : s.toCharArray()) { 
-      if (Character.isAlphabetic(c) || Character.isDigit(c) || c == '.') 
-        b.append(c); 
-      else 
-        b.append('-'); 
+      if (Utilities.isValidHtmlAnchorChar(c)) {
+        b.append(c);
+      } else {
+        b.append("|"+Integer.toHexString(c)); // not % to save double coding confusing users
+      }
     } 
     return b.toString(); 
   } 
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/OperationOutcomeRenderer.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/OperationOutcomeRenderer.java
index b725fa17f..8e9e8ef6b 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/OperationOutcomeRenderer.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/OperationOutcomeRenderer.java
@@ -88,8 +88,9 @@ public class OperationOutcomeRenderer extends ResourceRenderer {
             d = true; 
           td.addText(s.primitiveValue()); 
         } 
-        tr.td().addText(getTranslatedCode(i.child("code"))); 
-        tr.td().addText(i.child("details").primitiveValue("text")); 
+        tr.td().addText(getTranslatedCode(i.child("code")));
+        if (i.has("details"))
+          tr.td().addText(i.child("details").primitiveValue("text"));
         smartAddText(tr.td(), i.primitiveValue("diagnostics")); 
         if (hasSource) { 
           ResourceWrapper ext = i.extension(ToolingExtensions.EXT_ISSUE_SOURCE); 
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/ValueSetRenderer.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/ValueSetRenderer.java
index bb56a2f37..874aff02c 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/ValueSetRenderer.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/renderers/ValueSetRenderer.java
@@ -809,7 +809,8 @@ public class ValueSetRenderer extends TerminologyRenderer {
     XhtmlNode td = tr.td();
 
     String tgt = makeAnchor(c.getSystem(), c.getCode());
-    td.an(res.getScopedId()+"-"+context.prefixAnchor(tgt));
+    String pfx = res.getScopedId();
+    td.an((context.prefixAnchor(pfx == null ? "" : pfx+"-")+tgt));
 
     if (doLevel) {
       td.addText(Integer.toString(i));
diff --git a/org.hl7.fhir.report/pom.xml b/org.hl7.fhir.report/pom.xml
index 02f4536d5..b35def4d7 100644
--- a/org.hl7.fhir.report/pom.xml
+++ b/org.hl7.fhir.report/pom.xml
@@ -5,7 +5,7 @@
     <parent>
         <groupId>ca.uhn.hapi.fhir</groupId>
         <artifactId>org.hl7.fhir.core</artifactId>
-        <version>6.3.18-SNAPSHOT</version>
+        <version>6.3.19-SNAPSHOT</version>
         <relativePath>../pom.xml</relativePath>
     </parent>
 
diff --git a/org.hl7.fhir.utilities/pom.xml b/org.hl7.fhir.utilities/pom.xml
index 8aceebda8..d85e557e8 100644
--- a/org.hl7.fhir.utilities/pom.xml
+++ b/org.hl7.fhir.utilities/pom.xml
@@ -5,7 +5,7 @@
     <parent>
         <groupId>ca.uhn.hapi.fhir</groupId>
         <artifactId>org.hl7.fhir.core</artifactId>
-        <version>6.3.18-SNAPSHOT</version>
+        <version>6.3.19-SNAPSHOT</version>
         <relativePath>../pom.xml</relativePath>
     </parent>
 
diff --git a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/Utilities.java b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/Utilities.java
index 3e863ae59..9019581bb 100644
--- a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/Utilities.java
+++ b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/Utilities.java
@@ -2254,4 +2254,34 @@ public class Utilities {
     }
   }
 
+  public static boolean isValidHtmlAnchorChar(char c) {
+    if ( (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9')) {
+      return true;
+    } 
+    switch (c) {
+    case '!':
+    case '$':
+    case '&':
+    case '\'':
+    case '(':
+    case ')':
+    case '*':
+    case '+':
+    case ',':
+    case ';':
+    case '=':
+    case '.':
+    case '_':
+    case '-':
+    case '~':
+    case ':':
+    case '@':
+    case '/':
+    case '?':
+      return true;
+    default:
+      return false;
+    }
+  }
+
 }
diff --git a/org.hl7.fhir.validation.cli/pom.xml b/org.hl7.fhir.validation.cli/pom.xml
index 87bd293b4..8207c2a62 100644
--- a/org.hl7.fhir.validation.cli/pom.xml
+++ b/org.hl7.fhir.validation.cli/pom.xml
@@ -5,7 +5,7 @@
     <parent>
         <groupId>ca.uhn.hapi.fhir</groupId>
         <artifactId>org.hl7.fhir.core</artifactId>
-        <version>6.3.18-SNAPSHOT</version>
+        <version>6.3.19-SNAPSHOT</version>
         <relativePath>../pom.xml</relativePath>
     </parent>
 
diff --git a/org.hl7.fhir.validation/pom.xml b/org.hl7.fhir.validation/pom.xml
index 157e101f8..9fe3c30ab 100644
--- a/org.hl7.fhir.validation/pom.xml
+++ b/org.hl7.fhir.validation/pom.xml
@@ -5,7 +5,7 @@
     <parent>
         <groupId>ca.uhn.hapi.fhir</groupId>
         <artifactId>org.hl7.fhir.core</artifactId>
-        <version>6.3.18-SNAPSHOT</version>
+        <version>6.3.19-SNAPSHOT</version>
         <relativePath>../pom.xml</relativePath>
     </parent>
 
diff --git a/pom.xml b/pom.xml
index 02ae4285d..ed63737a6 100644
--- a/pom.xml
+++ b/pom.xml
@@ -14,7 +14,7 @@
     HAPI FHIR
     -->
     <artifactId>org.hl7.fhir.core</artifactId>
-    <version>6.3.18-SNAPSHOT</version>
+    <version>6.3.19-SNAPSHOT</version>
     <packaging>pom</packaging>
 
     <properties>