diff --git a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/misc/VSACImporter.java b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/misc/VSACImporter.java
index 90cc8c7ab..5e098382e 100644
--- a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/misc/VSACImporter.java
+++ b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/misc/VSACImporter.java
@@ -29,7 +29,7 @@ public class VSACImporter extends OIDBasedValueSetImporter {
     CSVReader csv = new CSVReader(new FileInputStream(source));
     csv.readHeaders();
 
-    FHIRToolingClient fhirToolingClient = new FHIRToolingClient("https://cts.nlm.nih.gov/fhir");
+    FHIRToolingClient fhirToolingClient = new FHIRToolingClient("https://cts.nlm.nih.gov/fhir", "fhir/vsac");
     fhirToolingClient.setUsername(username);
     fhirToolingClient.setPassword(password);
 
diff --git a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientFactory.java b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientFactory.java
index 59e901f95..28b26785d 100644
--- a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientFactory.java
+++ b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientFactory.java
@@ -39,42 +39,42 @@ import java.net.URISyntaxException;
 
 public class TerminologyClientFactory {
 
-  public static TerminologyClient makeClient(String url, FhirPublication v) throws URISyntaxException {
+  public static TerminologyClient makeClient(String url, String userAgent, FhirPublication v) throws URISyntaxException {
     if (v == null)
-      return new TerminologyClientR5(checkEndsWith("/r4", url));
+      return new TerminologyClientR5(checkEndsWith("/r4", url), userAgent);
     switch (v) {
       case DSTU2016May:
-        return new TerminologyClientR3(checkEndsWith("/r3", url)); // r3 is the least worst match
+        return new TerminologyClientR3(checkEndsWith("/r3", url), userAgent); // r3 is the least worst match
       case DSTU1:
         throw new Error("The version " + v + " is not currently supported");
       case DSTU2:
-        return new TerminologyClientR2(checkEndsWith("/r2", url));
+        return new TerminologyClientR2(checkEndsWith("/r2", url), userAgent);
       case R4:
-        return new TerminologyClientR5(checkEndsWith("/r4", url));
+        return new TerminologyClientR5(checkEndsWith("/r4", url), userAgent);
       case R5:
-        return new TerminologyClientR5(checkEndsWith("/r4", url)); // r4 for now, since the terminology is currently the same
+        return new TerminologyClientR5(checkEndsWith("/r4", url), userAgent); // r4 for now, since the terminology is currently the same
       case STU3:
-        return new TerminologyClientR3(checkEndsWith("/r3", url));
+        return new TerminologyClientR3(checkEndsWith("/r3", url), userAgent);
       default:
         throw new Error("The version " + v + " is not currently supported");
     }
   }
 
-  public static TerminologyClient makeClient(String url, String v) throws URISyntaxException {
+  public static TerminologyClient makeClient(String url, String userAgent, String v) throws URISyntaxException {
     if (v == null)
-      return new TerminologyClientR5(checkEndsWith("/r4", url));
+      return new TerminologyClientR5(checkEndsWith("/r4", url), userAgent);
     v = VersionUtilities.getMajMin(v);
     switch (v) {
       case "1.0":
-        return new TerminologyClientR2(checkEndsWith("/r2", url));
+        return new TerminologyClientR2(checkEndsWith("/r2", url), userAgent);
       case "1.4":
-        return new TerminologyClientR3(checkEndsWith("/r3", url)); // r3 is the least worst match
+        return new TerminologyClientR3(checkEndsWith("/r3", url), userAgent); // r3 is the least worst match
       case "3.0":
-        return new TerminologyClientR3(checkEndsWith("/r3", url));
+        return new TerminologyClientR3(checkEndsWith("/r3", url), userAgent);
       case "4.0":
-        return new TerminologyClientR4(checkEndsWith("/r4", url));
+        return new TerminologyClientR4(checkEndsWith("/r4", url), userAgent);
       case "4.5":
-        return new TerminologyClientR5(checkEndsWith("/r4", url)); // r4 for now, since the terminology is currently the same
+        return new TerminologyClientR5(checkEndsWith("/r4", url), userAgent); // r4 for now, since the terminology is currently the same
       default:
         throw new Error("The version " + v + " is not currently supported");
     }
diff --git a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR2.java b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR2.java
index 7675cf011..5c5fbb69e 100644
--- a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR2.java
+++ b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR2.java
@@ -48,8 +48,8 @@ public class TerminologyClientR2 implements TerminologyClient {
 
   private final FHIRToolingClient client; // todo: use the R2 client
 
-  public TerminologyClientR2(String address) throws URISyntaxException {
-    client = new FHIRToolingClient(address);
+  public TerminologyClientR2(String address, String userAgent) throws URISyntaxException {
+    client = new FHIRToolingClient(address, userAgent);
   }
 
   @Override
@@ -153,4 +153,10 @@ public class TerminologyClientR2 implements TerminologyClient {
   public TerminologyClient setClientHeaders(ClientHeaders clientHeaders) {
     return null;
   }
+
+  @Override
+  public TerminologyClient setUserAgent(String userAgent) {
+    client.setUserAgent(userAgent);
+    return this;
+  }
 }
\ No newline at end of file
diff --git a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR3.java b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR3.java
index fe4b1e607..68f03ba60 100644
--- a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR3.java
+++ b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR3.java
@@ -49,13 +49,13 @@ public class TerminologyClientR3 implements TerminologyClient {
   private final FHIRToolingClient client; // todo: use the R2 client
   private ClientHeaders clientHeaders;
 
-  public TerminologyClientR3(String address) throws URISyntaxException {
-    client = new FHIRToolingClient(address);
+  public TerminologyClientR3(String address, String userAgent) throws URISyntaxException {
+    client = new FHIRToolingClient(address, userAgent);
     setClientHeaders(new ClientHeaders());
   }
 
-  public TerminologyClientR3(String address, ClientHeaders clientHeaders) throws URISyntaxException {
-    client = new FHIRToolingClient(address);
+  public TerminologyClientR3(String address, String userAgent, ClientHeaders clientHeaders) throws URISyntaxException {
+    client = new FHIRToolingClient(address, userAgent);
     setClientHeaders(clientHeaders);
   }
 
@@ -162,4 +162,10 @@ public class TerminologyClientR3 implements TerminologyClient {
     this.client.setClientHeaders(this.clientHeaders.headers());
     return this;
   }
+
+  @Override
+  public TerminologyClient setUserAgent(String userAgent) {
+    client.setUserAgent(userAgent);
+    return this;
+ }
 }
\ No newline at end of file
diff --git a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR4.java b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR4.java
index 608ab860f..d9e6431e0 100644
--- a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR4.java
+++ b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR4.java
@@ -49,13 +49,13 @@ public class TerminologyClientR4 implements TerminologyClient {
   private final FHIRToolingClient client; // todo: use the R2 client
   private ClientHeaders clientHeaders;
 
-  public TerminologyClientR4(String address) throws URISyntaxException {
-    this.client = new FHIRToolingClient(address);
+  public TerminologyClientR4(String address, String userAgent) throws URISyntaxException {
+    this.client = new FHIRToolingClient(address, userAgent);
     setClientHeaders(new ClientHeaders());
   }
 
-  public TerminologyClientR4(String address, ClientHeaders clientHeaders) throws URISyntaxException {
-    this.client = new FHIRToolingClient(address);
+  public TerminologyClientR4(String address, String userAgent, ClientHeaders clientHeaders) throws URISyntaxException {
+    this.client = new FHIRToolingClient(address, userAgent);
     setClientHeaders(clientHeaders);
   }
 
@@ -162,4 +162,10 @@ public class TerminologyClientR4 implements TerminologyClient {
     this.client.setClientHeaders(this.clientHeaders.headers());
     return this;
   }
+
+  @Override
+  public TerminologyClient setUserAgent(String userAgent) {
+    client.setUserAgent(userAgent);
+    return this;
+  }
 }
\ No newline at end of file
diff --git a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR5.java b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR5.java
index f3c9041bd..cffbc1503 100644
--- a/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR5.java
+++ b/org.hl7.fhir.convertors/src/main/java/org/hl7/fhir/convertors/txClient/TerminologyClientR5.java
@@ -46,13 +46,13 @@ public class TerminologyClientR5 implements TerminologyClient {
   private final FHIRToolingClient client;
   private ClientHeaders clientHeaders;
 
-  public TerminologyClientR5(String address) throws URISyntaxException {
-    this.client = new FHIRToolingClient(address);
+  public TerminologyClientR5(String address, String userAgent) throws URISyntaxException {
+    this.client = new FHIRToolingClient(address, userAgent);
     setClientHeaders(new ClientHeaders());
   }
 
-  public TerminologyClientR5(String address, ClientHeaders clientHeaders) throws URISyntaxException {
-    this.client = new FHIRToolingClient(address);
+  public TerminologyClientR5(String address, String userAgent, ClientHeaders clientHeaders) throws URISyntaxException {
+    this.client = new FHIRToolingClient(address, userAgent);
     setClientHeaders(clientHeaders);
   }
 
@@ -148,4 +148,10 @@ public class TerminologyClientR5 implements TerminologyClient {
     this.client.setClientHeaders(this.clientHeaders.headers());
     return this;
   }
+
+  @Override
+  public TerminologyClient setUserAgent(String userAgent) {
+    client.setUserAgent(userAgent);
+    return this;
+  }
 }
\ No newline at end of file
diff --git a/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/BatchLoader.java b/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/BatchLoader.java
index f3471674a..30d734c20 100644
--- a/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/BatchLoader.java
+++ b/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/BatchLoader.java
@@ -117,7 +117,7 @@ public class BatchLoader {
   
 	private static int loadBundle(String server, Bundle b, int size, int start, int end) throws URISyntaxException {
 		System.out.println("Post to "+server+". size = "+Integer.toString(size)+", start = "+Integer.toString(start)+", total = "+Integer.toString(b.getEntry().size()));
-		FHIRToolingClient client = new FHIRToolingClient(server);
+		FHIRToolingClient client = new FHIRToolingClient(server, "fhir/batch-loader");
 	  int c = start;
 	  if (end == -1)
 	    end = b.getEntry().size();
diff --git a/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/SimpleWorkerContext.java b/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/SimpleWorkerContext.java
index f4d814220..f64a7dbbe 100644
--- a/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/SimpleWorkerContext.java
+++ b/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/SimpleWorkerContext.java
@@ -111,8 +111,8 @@ public class SimpleWorkerContext extends BaseWorkerContext implements IWorkerCon
 		return res;
 	}
 
-	public void connectToTSServer(String url) throws URISyntaxException {
-	  txServer = new FHIRToolingClient(url);
+	public void connectToTSServer(String url, String userAgent) throws URISyntaxException {
+	  txServer = new FHIRToolingClient(url, userAgent);
 	}
 
 	private void loadFromFile(InputStream stream, String name) throws IOException, FHIRException {
diff --git a/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/client/ClientUtils.java b/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/client/ClientUtils.java
index ce0e570e5..d23354272 100644
--- a/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/client/ClientUtils.java
+++ b/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/client/ClientUtils.java
@@ -105,6 +105,7 @@ public class ClientUtils {
   private String password;
   private ToolingClientLogger logger;
   private int retryCount;
+  private String userAgent;
 
   public HttpHost getProxy() {
     return proxy;
@@ -258,7 +259,9 @@ public class ClientUtils {
    * @param request
    */
   protected void configureFhirRequest(HttpRequest request, String format, List<Header> headers) {
-    request.addHeader("User-Agent", "Java FHIR Client for FHIR");
+    if (!Utilities.noString(userAgent)) {
+      request.addHeader("User-Agent", userAgent);
+    }
 
     if (format != null) {		
       request.addHeader("Accept",format);
@@ -663,5 +666,13 @@ public class ClientUtils {
     this.retryCount = retryCount;
   }
 
+  public String getUserAgent() {
+    return userAgent;
+  }
+
+  public void setUserAgent(String userAgent) {
+    this.userAgent = userAgent;
+  }
+
 
 }
\ No newline at end of file
diff --git a/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/client/FHIRToolingClient.java b/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/client/FHIRToolingClient.java
index ad7fb0bf6..5308f7c98 100644
--- a/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/client/FHIRToolingClient.java
+++ b/org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/utils/client/FHIRToolingClient.java
@@ -100,14 +100,16 @@ public class FHIRToolingClient {
 	private ClientUtils utils = new ClientUtils();
 	
 	//Pass enpoint for client - URI
-	public FHIRToolingClient(String baseServiceUrl) throws URISyntaxException {
+	public FHIRToolingClient(String baseServiceUrl, String userAgent) throws URISyntaxException {
 		preferredResourceFormat = ResourceFormat.RESOURCE_XML;
+    utils.setUserAgent(userAgent);
     detectProxy();
     initialize(baseServiceUrl);
 	}
 
-  public FHIRToolingClient(String baseServiceUrl, String username, String password) throws URISyntaxException {
+  public FHIRToolingClient(String baseServiceUrl, String userAgent, String username, String password) throws URISyntaxException {
     preferredResourceFormat = ResourceFormat.RESOURCE_XML;
+    utils.setUserAgent(userAgent);
     utils.setUsername(username);
     utils.setPassword(password);
     detectProxy();
@@ -857,5 +859,11 @@ public class FHIRToolingClient {
     utils.setRetryCount(retryCount);
   }
 
+  public String getUserAgent() {
+    return utils.getUserAgent();
+  }
 
+  public void setUserAgent(String userAgent) {
+    utils.setUserAgent(userAgent);
+  }
 }
\ No newline at end of file
diff --git a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/context/SimpleWorkerContext.java b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/context/SimpleWorkerContext.java
index 080ed1952..35bd0485f 100644
--- a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/context/SimpleWorkerContext.java
+++ b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/context/SimpleWorkerContext.java
@@ -218,8 +218,8 @@ public class SimpleWorkerContext extends BaseWorkerContext implements IWorkerCon
       loadBytes(name, stream);
   }
 
-	public String connectToTSServer(String url) throws URISyntaxException {
-	  txServer = new FHIRToolingClient(url);
+	public String connectToTSServer(String url, String userAgent) throws URISyntaxException {
+	  txServer = new FHIRToolingClient(url, userAgent);
 	  txServer.setTimeout(30000);
 	  return txServer.getCapabilitiesStatementQuick().getSoftware().getVersion();
 	}
diff --git a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/BatchLoader.java b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/BatchLoader.java
index 2fb645802..15664a992 100644
--- a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/BatchLoader.java
+++ b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/BatchLoader.java
@@ -80,7 +80,7 @@ public class BatchLoader {
 
   private static void LoadDirectory(String server, String folder, int size) throws IOException, Exception {
     System.out.print("Connecting to "+server+".. ");
-    FHIRToolingClient client = new FHIRToolingClient(server);
+    FHIRToolingClient client = new FHIRToolingClient(server, "fhir/batch-loader");
     System.out.println("Done");
     
     IniFile ini = new IniFile(Utilities.path(folder, "batch-load-progress.ini"));
diff --git a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/client/FHIRToolingClient.java b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/client/FHIRToolingClient.java
index d09faeaef..8239deb2e 100644
--- a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/client/FHIRToolingClient.java
+++ b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/client/FHIRToolingClient.java
@@ -66,10 +66,12 @@ public class FHIRToolingClient {
   private ArrayList<Header> headers = new ArrayList<>();
   private String username;
   private String password;
+  private String userAgent;
 
   //Pass endpoint for client - URI
-  public FHIRToolingClient(String baseServiceUrl) throws URISyntaxException {
+  public FHIRToolingClient(String baseServiceUrl, String userAgent) throws URISyntaxException {
     preferredResourceFormat = ResourceFormat.RESOURCE_XML;
+    this.userAgent = userAgent;
     initialize(baseServiceUrl);
   }
 
@@ -280,7 +282,7 @@ public class FHIRToolingClient {
       if (client.getLogger() != null) {
         client.getLogger().logRequest("POST", url.toString(), null, body);
       }
-      result = client.issuePostRequest(url, body, getPreferredResourceFormat(),
+      result = client.issuePostRequest(url, body, getPreferredResourceFormat(), generateHeaders(),
           "POST " + resourceClass.getName() + "/$" + name, TIMEOUT_OPERATION_LONG);
     } else {
       if (client.getLogger() != null) {
@@ -555,6 +557,9 @@ public class FHIRToolingClient {
     if(this.headers != null) {
       this.headers.forEach(header -> builder.add(header.toString()));
     }
+    if (!Utilities.noString(userAgent)) {
+      builder.add("User-Agent: "+userAgent);
+    }
     return builder.build();
   }
 
@@ -567,5 +572,13 @@ public class FHIRToolingClient {
     String base64usernamePassword = Base64.getEncoder().encodeToString(usernamePassword.getBytes());
     return new Header("Authorization", "Basic " + base64usernamePassword);
   }
+  
+  public String getUserAgent() {
+    return userAgent;
+  }
+
+  public void setUserAgent(String userAgent) {
+    this.userAgent = userAgent;
+  }
 }
 
diff --git a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/client/network/FhirRequestBuilder.java b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/client/network/FhirRequestBuilder.java
index 0537c3211..3508a9adb 100644
--- a/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/client/network/FhirRequestBuilder.java
+++ b/org.hl7.fhir.dstu3/src/main/java/org/hl7/fhir/dstu3/utils/client/network/FhirRequestBuilder.java
@@ -63,7 +63,7 @@ public class FhirRequestBuilder {
    * @param headers Any additional {@link Headers} to add to the request.
    */
   protected static void formatHeaders(Request.Builder request, String format, Headers headers) {
-    addDefaultHeaders(request);
+    addDefaultHeaders(request, headers);
     if (format != null) addResourceFormatHeaders(request, format);
     if (headers != null) addHeaders(request, headers);
   }
@@ -75,8 +75,10 @@ public class FhirRequestBuilder {
    *
    * @param request {@link Request.Builder} to add default headers to.
    */
-  protected static void addDefaultHeaders(Request.Builder request) {
-    request.addHeader("User-Agent", "hapi-fhir-tooling-client");
+  protected static void addDefaultHeaders(Request.Builder request, Headers headers) {
+    if (headers == null || !headers.names().contains("User-Agent")) {
+      request.addHeader("User-Agent", "hapi-fhir-tooling-client");
+    }
     request.addHeader("Accept-Charset", DEFAULT_CHARSET);
   }
 
@@ -203,7 +205,7 @@ public class FhirRequestBuilder {
   }
 
   public <T extends Resource> ResourceRequest<T> execute() throws IOException {
-    formatHeaders(httpRequest, resourceFormat, null);
+    formatHeaders(httpRequest, resourceFormat, headers);
     Response response = getHttpClient().newCall(httpRequest.build()).execute();
     T resource = unmarshalReference(response, resourceFormat);
     return new ResourceRequest<T>(resource, response.code(), getLocationHeader(response.headers()));
diff --git a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/terminologies/TerminologyClientR4.java b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/terminologies/TerminologyClientR4.java
index 2c268b020..a21f9ade0 100644
--- a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/terminologies/TerminologyClientR4.java
+++ b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/terminologies/TerminologyClientR4.java
@@ -46,8 +46,8 @@ public class TerminologyClientR4 implements TerminologyClient {
 
   private FHIRToolingClient client;
   
-  public TerminologyClientR4(String address) throws URISyntaxException {
-    client = new FHIRToolingClient(address);
+  public TerminologyClientR4(String address, String userAgent) throws URISyntaxException {
+    client = new FHIRToolingClient(address, userAgent);
   }
 
   @Override
diff --git a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/utils/BatchLoader.java b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/utils/BatchLoader.java
index da8702005..7e3b66bcd 100644
--- a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/utils/BatchLoader.java
+++ b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/utils/BatchLoader.java
@@ -80,7 +80,7 @@ public class BatchLoader {
 
 	private static void LoadDirectory(String server, String folder, int size) throws IOException, Exception {
 	  System.out.print("Connecting to "+server+".. ");
-	  FHIRToolingClient client = new FHIRToolingClient(server);
+	  FHIRToolingClient client = new FHIRToolingClient(server, "fhir/batch-loader");
     System.out.println("Done");
 	  
 	  IniFile ini = new IniFile(Utilities.path(folder, "batch-load-progress.ini"));
diff --git a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/utils/client/FHIRToolingClient.java b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/utils/client/FHIRToolingClient.java
index 8ec5c4abc..c45db06a2 100644
--- a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/utils/client/FHIRToolingClient.java
+++ b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/utils/client/FHIRToolingClient.java
@@ -63,10 +63,12 @@ public class FHIRToolingClient {
   private ArrayList<Header> headers = new ArrayList<>();
   private String username;
   private String password;
+  private String userAgent;
 
   //Pass endpoint for client - URI
-  public FHIRToolingClient(String baseServiceUrl) throws URISyntaxException {
+  public FHIRToolingClient(String baseServiceUrl, String userAgent) throws URISyntaxException {
     preferredResourceFormat = ResourceFormat.RESOURCE_XML;
+    this.userAgent = userAgent;
     initialize(baseServiceUrl);
   }
 
@@ -277,7 +279,7 @@ public class FHIRToolingClient {
         if (client.getLogger() != null) {
           client.getLogger().logRequest("POST", url.toString(), null, body);
         }
-        result = client.issuePostRequest(url, body, getPreferredResourceFormat(),
+        result = client.issuePostRequest(url, body, getPreferredResourceFormat(), generateHeaders(),
             "POST " + resourceClass.getName() + "/$" + name, TIMEOUT_OPERATION_LONG);
       } else {
         if (client.getLogger() != null) {
@@ -528,6 +530,9 @@ public class FHIRToolingClient {
     if(this.headers != null) {
       this.headers.forEach(header -> builder.add(header.toString()));
     }
+    if (!Utilities.noString(userAgent)) {
+      builder.add("User-Agent: "+userAgent);
+    }
     return builder.build();
   }
 
@@ -540,5 +545,13 @@ public class FHIRToolingClient {
     String base64usernamePassword = Base64.getEncoder().encodeToString(usernamePassword.getBytes());
     return new Header("Authorization", "Basic " + base64usernamePassword);
   }
+  
+  public String getUserAgent() {
+    return userAgent;
+  }
+
+  public void setUserAgent(String userAgent) {
+    this.userAgent = userAgent;
+  }
 }
 
diff --git a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/utils/client/network/FhirRequestBuilder.java b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/utils/client/network/FhirRequestBuilder.java
index 10235d77a..b34ce59dd 100644
--- a/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/utils/client/network/FhirRequestBuilder.java
+++ b/org.hl7.fhir.r4/src/main/java/org/hl7/fhir/r4/utils/client/network/FhirRequestBuilder.java
@@ -63,7 +63,7 @@ public class FhirRequestBuilder {
    * @param headers Any additional {@link Headers} to add to the request.
    */
   protected static void formatHeaders(Request.Builder request, String format, Headers headers) {
-    addDefaultHeaders(request);
+    addDefaultHeaders(request, headers);
     if (format != null) addResourceFormatHeaders(request, format);
     if (headers != null) addHeaders(request, headers);
   }
@@ -75,8 +75,10 @@ public class FhirRequestBuilder {
    *
    * @param request {@link Request.Builder} to add default headers to.
    */
-  protected static void addDefaultHeaders(Request.Builder request) {
-    request.addHeader("User-Agent", "hapi-fhir-tooling-client");
+  protected static void addDefaultHeaders(Request.Builder request, Headers headers) {
+    if (headers == null || !headers.names().contains("User-Agent")) {
+      request.addHeader("User-Agent", "hapi-fhir-tooling-client");
+    }
     request.addHeader("Accept-Charset", DEFAULT_CHARSET);
   }
 
@@ -203,7 +205,7 @@ public class FhirRequestBuilder {
   }
 
   public <T extends Resource> ResourceRequest<T> execute() throws IOException {
-    formatHeaders(httpRequest, resourceFormat, null);
+    formatHeaders(httpRequest, resourceFormat, headers);
     Response response = getHttpClient().newCall(httpRequest.build()).execute();
     T resource = unmarshalReference(response, resourceFormat);
     return new ResourceRequest<T>(resource, response.code(), getLocationHeader(response.headers()));
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/comparison/ValueSetComparer.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/comparison/ValueSetComparer.java
index 7ce597134..1d0543b84 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/comparison/ValueSetComparer.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/comparison/ValueSetComparer.java
@@ -394,7 +394,7 @@ public class ValueSetComparer extends CanonicalResourceComparer {
 
   private void compareExpansions(ValueSet left, ValueSet right, ValueSetComparison res) {
     ValueSet expL = left.hasExpansion() ? left : expand(left, res, "left", session.getContextLeft());
-    ValueSet expR = left.hasExpansion() ? left : expand(right, res, "right", session.getContextRight());
+    ValueSet expR = right.hasExpansion() ? right : expand(right, res, "right", session.getContextRight());
     if (expL != null && expR != null) {
       // ignore the parameters for now
       compareConcepts(expL.getExpansion().getContains(), expR.getExpansion().getContains(), res.forceExpansion(), res.getUnion().getExpansion().getContains(), res.getIntersection().getExpansion().getContains(), "ValueSet.expansion.contains", res);
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/BaseWorkerContext.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/BaseWorkerContext.java
index a997271fe..f441447a4 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/BaseWorkerContext.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/BaseWorkerContext.java
@@ -207,6 +207,7 @@ public abstract class BaseWorkerContext extends I18nBase implements IWorkerConte
   protected TimeTracker clock;
   private boolean tlogging = true;
   private ICanonicalResourceLocator locator;
+  protected String userAgent;
   
   public BaseWorkerContext() throws FileNotFoundException, IOException, FHIRException {
     txCache = new TerminologyCache(lock, null);
@@ -2100,4 +2101,14 @@ public abstract class BaseWorkerContext extends I18nBase implements IWorkerConte
     this.locator = locator;
   }
 
+  public String getUserAgent() {
+    return userAgent;
+  }
+
+  public void setUserAgent(String userAgent) {
+    this.userAgent = userAgent;
+    if (txClient != null)
+      txClient.setUserAgent(userAgent);
+  }
+
 }
\ No newline at end of file
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/SimpleWorkerContext.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/SimpleWorkerContext.java
index 50664d0c7..7e132e33b 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/SimpleWorkerContext.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/SimpleWorkerContext.java
@@ -296,6 +296,7 @@ public class SimpleWorkerContext extends BaseWorkerContext implements IWorkerCon
         txLog = new HTMLClientLogger(log);
       }
       txClient.setLogger(txLog);
+      txClient.setUserAgent(userAgent);
       CapabilityStatement cps = txClient.getCapabilitiesStatementQuick();
       setTxCaps(txClient.getTerminologyCapabilities());
       return cps.getSoftware().getVersion();
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/terminologies/TerminologyClient.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/terminologies/TerminologyClient.java
index 1582d3689..2d4c4f291 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/terminologies/TerminologyClient.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/terminologies/TerminologyClient.java
@@ -54,4 +54,5 @@ public interface TerminologyClient {
   CanonicalResource read(String type, String id);
   ClientHeaders getClientHeaders();
   TerminologyClient setClientHeaders(ClientHeaders clientHeaders);
+  TerminologyClient setUserAgent(String userAgent);
 }
\ No newline at end of file
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/BatchLoader.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/BatchLoader.java
index 43364a685..64a308b93 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/BatchLoader.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/BatchLoader.java
@@ -117,7 +117,7 @@ public class BatchLoader {
   
 	private static int loadBundle(String server, Bundle b, int size, int start, int end) throws URISyntaxException {
 		System.out.println("Post to "+server+". size = "+Integer.toString(size)+", start = "+Integer.toString(start)+", total = "+Integer.toString(b.getEntry().size()));
-		FHIRToolingClient client = new FHIRToolingClient(server);
+		FHIRToolingClient client = new FHIRToolingClient(server, "fhir/batch-loader");
 	  int c = start;
 	  if (end == -1)
 	    end = b.getEntry().size();
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/FHIRToolingClient.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/FHIRToolingClient.java
index 66e93dc91..ade033db5 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/FHIRToolingClient.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/FHIRToolingClient.java
@@ -95,10 +95,12 @@ public class FHIRToolingClient {
   private ArrayList<Header> headers = new ArrayList<>();
   private String username;
   private String password;
+  private String userAgent;
 
   //Pass endpoint for client - URI
-  public FHIRToolingClient(String baseServiceUrl) throws URISyntaxException {
+  public FHIRToolingClient(String baseServiceUrl, String userAgent) throws URISyntaxException {
     preferredResourceFormat = ResourceFormat.RESOURCE_XML;
+    this.userAgent = userAgent;
     initialize(baseServiceUrl);
   }
 
@@ -309,7 +311,7 @@ public class FHIRToolingClient {
         if (client.getLogger() != null) {
           client.getLogger().logRequest("POST", url.toString(), null, body);
         }
-        result = client.issuePostRequest(url, body, getPreferredResourceFormat(),
+        result = client.issuePostRequest(url, body, getPreferredResourceFormat(), generateHeaders(),
             "POST " + resourceClass.getName() + "/$" + name, TIMEOUT_OPERATION_LONG);
       } else {
         if (client.getLogger() != null) {
@@ -336,7 +338,9 @@ public class FHIRToolingClient {
   public Bundle transaction(Bundle batch) {
     Bundle transactionResult = null;
     try {
-      transactionResult = client.postBatchRequest(resourceAddress.getBaseServiceUri(), ByteUtils.resourceToByteArray(batch, false, isJson(getPreferredResourceFormat())), getPreferredResourceFormat(), "transaction", TIMEOUT_OPERATION + (TIMEOUT_ENTRY * batch.getEntry().size()));
+      transactionResult = client.postBatchRequest(resourceAddress.getBaseServiceUri(), ByteUtils.resourceToByteArray(batch, false, isJson(getPreferredResourceFormat())), getPreferredResourceFormat(),
+          generateHeaders(),
+          "transaction", TIMEOUT_OPERATION + (TIMEOUT_ENTRY * batch.getEntry().size()));
     } catch (Exception e) {
       handleException("An error occurred trying to process this transaction request", e);
     }
@@ -560,6 +564,9 @@ public class FHIRToolingClient {
     if(this.headers != null) {
       this.headers.forEach(header -> builder.add(header.toString()));
     }
+    if (!Utilities.noString(userAgent)) {
+      builder.add("User-Agent: "+userAgent);
+    }
     return builder.build();
   }
 
@@ -572,5 +579,15 @@ public class FHIRToolingClient {
     String base64usernamePassword = Base64.getEncoder().encodeToString(usernamePassword.getBytes());
     return new Header("Authorization", "Basic " + base64usernamePassword);
   }
+
+  public String getUserAgent() {
+    return userAgent;
+  }
+
+  public void setUserAgent(String userAgent) {
+    this.userAgent = userAgent;
+  }
+  
+  
 }
 
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/network/Client.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/network/Client.java
index 485c9222e..f24e054fa 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/network/Client.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/network/Client.java
@@ -149,6 +149,7 @@ public class Client {
   public Bundle postBatchRequest(URI resourceUri,
                                  byte[] payload,
                                  String resourceFormat,
+                                 Headers headers,
                                  String message,
                                  int timeout) throws IOException {
     if (payload == null) throw new EFhirClientException("POST requests require a non-null payload");
@@ -157,7 +158,7 @@ public class Client {
       .url(resourceUri.toURL())
       .post(body);
 
-    return executeBundleRequest(request, resourceFormat, new Headers.Builder().build(), message, retryCount, timeout);
+    return executeBundleRequest(request, resourceFormat, headers, message, retryCount, timeout);
   }
 
   public <T extends Resource> Bundle executeBundleRequest(Request.Builder request,
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/network/FhirRequestBuilder.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/network/FhirRequestBuilder.java
index e51a2c61e..1e55afe54 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/network/FhirRequestBuilder.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/network/FhirRequestBuilder.java
@@ -63,7 +63,7 @@ public class FhirRequestBuilder {
    * @param headers Any additional {@link Headers} to add to the request.
    */
   protected static void formatHeaders(Request.Builder request, String format, Headers headers) {
-    addDefaultHeaders(request);
+    addDefaultHeaders(request, headers);
     if (format != null) addResourceFormatHeaders(request, format);
     if (headers != null) addHeaders(request, headers);
   }
@@ -75,8 +75,10 @@ public class FhirRequestBuilder {
    *
    * @param request {@link Request.Builder} to add default headers to.
    */
-  protected static void addDefaultHeaders(Request.Builder request) {
-    request.addHeader("User-Agent", "hapi-fhir-tooling-client");
+  protected static void addDefaultHeaders(Request.Builder request, Headers headers) {
+    if (headers == null || !headers.names().contains("User-Agent")) {
+      request.addHeader("User-Agent", "hapi-fhir-tooling-client");
+    }
     request.addHeader("Accept-Charset", DEFAULT_CHARSET);
   }
 
@@ -203,7 +205,7 @@ public class FhirRequestBuilder {
   }
 
   public <T extends Resource> ResourceRequest<T> execute() throws IOException {
-    formatHeaders(httpRequest, resourceFormat, null);
+    formatHeaders(httpRequest, resourceFormat, headers);
     Response response = getHttpClient().newCall(httpRequest.build()).execute();
     T resource = unmarshalReference(response, resourceFormat);
     return new ResourceRequest<T>(resource, response.code(), getLocationHeader(response.headers()));
diff --git a/org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/utils/client/FHIRToolingClientTest.java b/org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/utils/client/FHIRToolingClientTest.java
index 1ff215ace..966392cf4 100644
--- a/org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/utils/client/FHIRToolingClientTest.java
+++ b/org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/utils/client/FHIRToolingClientTest.java
@@ -65,7 +65,7 @@ class FHIRToolingClientTest {
     Mockito.when(mockClient.executeBundleRequest(Mockito.any(Request.Builder.class), Mockito.anyString(),
       Mockito.any(Headers.class), Mockito.anyString(), Mockito.anyInt(), Mockito.anyLong()))
       .thenReturn(generateBundle());
-    toolingClient = new FHIRToolingClient(TX_ADDR);
+    toolingClient = new FHIRToolingClient(TX_ADDR, "fhir/test-cases");
     toolingClient.setClient(mockClient);
   }
 
diff --git a/org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/utils/client/network/FhirRequestBuilderTest.java b/org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/utils/client/network/FhirRequestBuilderTest.java
index 24cf3b21b..f7723339a 100644
--- a/org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/utils/client/network/FhirRequestBuilderTest.java
+++ b/org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/utils/client/network/FhirRequestBuilderTest.java
@@ -19,7 +19,7 @@ class FhirRequestBuilderTest {
   @DisplayName("Test default headers are added correctly.")
   void addDefaultHeaders() {
     Request.Builder request = new Request.Builder().url("http://www.google.com");
-    FhirRequestBuilder.addDefaultHeaders(request);
+    FhirRequestBuilder.addDefaultHeaders(request, null);
 
     Map<String, List<String>> headersMap = request.build().headers().toMultimap();
     Assertions.assertNotNull(headersMap.get("User-Agent"), "User-Agent header null.");
diff --git a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/json/JsonTrackingParser.java b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/json/JsonTrackingParser.java
index 977d6873b..6aed2851a 100644
--- a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/json/JsonTrackingParser.java
+++ b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/json/JsonTrackingParser.java
@@ -38,6 +38,7 @@ import java.io.InputStream;
 import java.math.BigDecimal;
 import java.net.HttpURLConnection;
 import java.net.URL;
+import java.nio.charset.StandardCharsets;
 import java.util.Map;
 import java.util.Stack;
 
@@ -674,6 +675,16 @@ public class JsonTrackingParser {
     return gson.toJson(json);    
   }
 
+  public static byte[] writeBytes(JsonObject json, boolean pretty) {
+    if (pretty) {
+      Gson gson = new GsonBuilder().setPrettyPrinting().create();
+      return gson.toJson(json).getBytes(StandardCharsets.UTF_8);    
+    } else {
+      Gson gson = new GsonBuilder().create();
+      return gson.toJson(json).getBytes(StandardCharsets.UTF_8);    
+    }    
+  }
+  
   public static JsonObject fetchJson(String source) throws IOException {
     URL url = new URL(source+"?nocache=" + System.currentTimeMillis());
     HttpURLConnection c = (HttpURLConnection) url.openConnection();
diff --git a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/npm/NpmPackage.java b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/npm/NpmPackage.java
index ae3bc4039..e377232f2 100644
--- a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/npm/NpmPackage.java
+++ b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/npm/NpmPackage.java
@@ -64,6 +64,7 @@ import org.hl7.fhir.utilities.TextFile;
 import org.hl7.fhir.utilities.Utilities;
 import org.hl7.fhir.utilities.json.JSONUtil;
 import org.hl7.fhir.utilities.json.JsonTrackingParser;
+import org.hl7.fhir.utilities.npm.NpmPackage.ITransformingLoader;
 import org.hl7.fhir.utilities.npm.NpmPackage.PackageResourceInformationSorter;
 import org.hl7.fhir.utilities.npm.PackageGenerator.PackageType;
 
@@ -84,6 +85,12 @@ import com.google.gson.JsonObject;
  */
 public class NpmPackage {
 
+  public interface ITransformingLoader {
+
+    byte[] load(File f);
+
+  }
+
   public class PackageResourceInformationSorter implements Comparator<PackageResourceInformation> {
     @Override
     public int compare(PackageResourceInformation o1, PackageResourceInformation o2) {
@@ -1054,6 +1061,18 @@ public class NpmPackage {
     }
   }
 
+  public void loadAllFiles(ITransformingLoader loader) throws IOException {
+    for (String folder : folders.keySet()) {
+      NpmPackageFolder pf = folders.get(folder);
+      String p = folder.contains("$") ? path : Utilities.path(path, folder);
+      for (File f : new File(p).listFiles()) {
+        if (!f.isDirectory() && !isInternalExemptFile(f)) {
+          pf.getContent().put(f.getName(), loader.load(f));
+        }
+      }
+    }
+  }
+
   public boolean isChangedByLoader() {
     return changedByLoader;
   }
diff --git a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/ValidationEngine.java b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/ValidationEngine.java
index b9ce471f9..db6957721 100644
--- a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/ValidationEngine.java
+++ b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/ValidationEngine.java
@@ -189,23 +189,26 @@ public class ValidationEngine implements IValidatorResourceFetcher, IPackageInst
     igLoader = new IgLoader(getPcm(), getContext(), getVersion(), isDebug());
   }
 
-  public ValidationEngine(String src, String txsrvr, String txLog, FhirPublication version, boolean canRunWithoutTerminologyServer, String vString) throws FHIRException, IOException, URISyntaxException {
+  public ValidationEngine(String src, String txsrvr, String txLog, FhirPublication version, boolean canRunWithoutTerminologyServer, String vString, String userAgent) throws FHIRException, IOException, URISyntaxException {
     loadCoreDefinitions(src, false, null);
+    getContext().setUserAgent(userAgent);
     getContext().setCanRunWithoutTerminology(canRunWithoutTerminologyServer);
     setTerminologyServer(txsrvr, txLog, version);
     setVersion(vString);
     igLoader = new IgLoader(getPcm(), getContext(), getVersion(), isDebug());
   }
 
-  public ValidationEngine(String src, String txsrvr, String txLog, FhirPublication version, String vString) throws FHIRException, IOException, URISyntaxException {
+  public ValidationEngine(String src, String txsrvr, String txLog, FhirPublication version, String vString, String userAgent) throws FHIRException, IOException, URISyntaxException {
     loadCoreDefinitions(src, false, null);
+    getContext().setUserAgent(userAgent);
     setTerminologyServer(txsrvr, txLog, version);
     setVersion(vString);
     igLoader = new IgLoader(getPcm(), getContext(), getVersion(), isDebug());
   }
 
-  public ValidationEngine(String src, String vString, TimeTracker tt) throws FHIRException, IOException, URISyntaxException {
+  public ValidationEngine(String src, String vString, TimeTracker tt, String userAgent) throws FHIRException, IOException, URISyntaxException {
     loadCoreDefinitions(src, false, tt);
+    getContext().setUserAgent(userAgent);
     setVersion(vString);
     igLoader = new IgLoader(getPcm(), getContext(), getVersion(), isDebug());
   }
@@ -271,7 +274,7 @@ public class ValidationEngine implements IValidatorResourceFetcher, IPackageInst
       return "n/a: No Terminology Server";
     } else {
       try {
-        return context.connectToTSServer(TerminologyClientFactory.makeClient(url, version), log);
+        return context.connectToTSServer(TerminologyClientFactory.makeClient(url, context.getUserAgent(), version), log);
       } catch (Exception e) {
         if (context.isCanRunWithoutTerminology()) {
           return "n/a: Running without Terminology Server (error: " + e.getMessage() + ")";
diff --git a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/services/StandAloneValidatorFetcher.java b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/services/StandAloneValidatorFetcher.java
index de2f5ed36..9eba19d20 100644
--- a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/services/StandAloneValidatorFetcher.java
+++ b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/services/StandAloneValidatorFetcher.java
@@ -231,7 +231,7 @@ public class StandAloneValidatorFetcher implements IValidatorResourceFetcher, IC
     String root = getRoot(p, url);
     if (root != null) {
       TerminologyClient c;
-      c = TerminologyClientFactory.makeClient(root, context.getVersion());
+      c = TerminologyClientFactory.makeClient(root, "fhir/validator", context.getVersion());
       return c.read(p[p.length - 2], p[p.length - 1]);
     } else {
       throw new FHIRException("The URL '" + url + "' is not known to the FHIR validator, and has not been provided as part of the setup / parameters");
diff --git a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/services/ValidationService.java b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/services/ValidationService.java
index 7a3dd680a..0c756e5d7 100644
--- a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/services/ValidationService.java
+++ b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/services/ValidationService.java
@@ -265,7 +265,7 @@ public class ValidationService {
         System.out.println("No such cached session exists for session id " + sessionId + ", re-instantiating validator.");
       }
       System.out.print("  Load FHIR v" + cliContext.getSv() + " from " + definitions);
-      ValidationEngine validator = new ValidationEngine(definitions, cliContext.getSv(), tt);
+      ValidationEngine validator = new ValidationEngine(definitions, cliContext.getSv(), tt, "fhir/validator");
       sessionId = sessionCache.cacheSession(validator);
 
       FhirPublication ver = FhirPublication.fromCode(cliContext.getSv());
diff --git a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/utils/Common.java b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/utils/Common.java
index 622756708..15ab65664 100644
--- a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/utils/Common.java
+++ b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/utils/Common.java
@@ -87,7 +87,7 @@ public class Common {
 
   public static ValidationEngine getValidationEngine(String version, String txServer, String definitions, String txLog, TimeTracker tt) throws Exception {
     System.out.println("Loading (v = " + version + ", tx server -> " + txServer + ")");
-    ValidationEngine ve = new ValidationEngine(definitions, version, tt);
+    ValidationEngine ve = new ValidationEngine(definitions, version, tt, "fhir/validator");
     ve.connectToTSServer(txServer, txLog, FhirPublication.fromCode(version));
     return ve;
   }
diff --git a/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/tests/ValidationEngineTests.java b/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/tests/ValidationEngineTests.java
index 0144c117d..0f82b2362 100644
--- a/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/tests/ValidationEngineTests.java
+++ b/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/tests/ValidationEngineTests.java
@@ -17,8 +17,8 @@ import org.junit.jupiter.api.Test;
 
 public class ValidationEngineTests {
 
-  private static final String DEF_TX = "http://tx.fhir.org";
-  private static final String DBG_TX = "http://local.fhir.org:960";
+//  public static final String DEF_TX = "http://tx.fhir.org";
+  public static final String DEF_TX = "http://local.fhir.org:960";
 
   public static boolean inbuild;
 
@@ -26,7 +26,7 @@ public class ValidationEngineTests {
   public void testCurrentXml() throws Exception {
     if (!TestUtilities.silent)
       System.out.println("TestCurrentXml: Validate patient-example.xml in Current version");
-    ValidationEngine ve = new ValidationEngine("hl7.fhir.r4.core#4.0.1", DEF_TX, null, FhirPublication.R4, "4.0.1");
+    ValidationEngine ve = new ValidationEngine("hl7.fhir.r4.core#4.0.1", DEF_TX, null, FhirPublication.R4, "4.0.1", "fhir/test-cases");
     OperationOutcome op = ve.validate(FhirFormat.XML, TestingUtilities.loadTestResourceStream("validator", "patient-example.xml"), null);
     int e = errors(op);
     int w = warnings(op);
@@ -46,7 +46,7 @@ public class ValidationEngineTests {
   public void testCurrentJson() throws Exception {
     if (!TestUtilities.silent)
       System.out.println("TestCurrentJson: Validate patient-example.json in Current version");
-    ValidationEngine ve = new ValidationEngine("hl7.fhir.r4.core#4.0.1", DEF_TX, null, FhirPublication.R4, "4.0.1");
+    ValidationEngine ve = new ValidationEngine("hl7.fhir.r4.core#4.0.1", DEF_TX, null, FhirPublication.R4, "4.0.1", "fhir/test-cases");
     OperationOutcome op = ve.validate(FhirFormat.JSON, TestingUtilities.loadTestResourceStream("validator", "patient-example.json"), null);
     int e = errors(op);
     int w = warnings(op);
@@ -66,8 +66,8 @@ public class ValidationEngineTests {
     }
     if (!TestUtilities.silent)
       System.out.println("Test140: Validate patient-example.xml in v1.4.0 version");
-    ValidationEngine ve = new ValidationEngine("hl7.fhir.r2b.core#1.4.0", DEF_TX, null, FhirPublication.DSTU2016May, "1.4.0");
-    ve.setNoInvariantChecks(true);
+    ValidationEngine ve = new ValidationEngine("hl7.fhir.r2b.core#1.4.0", DEF_TX, null, FhirPublication.DSTU2016May, "1.4.0", "fhir/test-cases");
+    ve.getContext().setUserAgent("fhir/test-cases");
     OperationOutcome op = ve.validate(FhirFormat.XML, TestingUtilities.loadTestResourceStream("validator", "patient140.xml"), null);
     if (!TestUtilities.silent)
       for (OperationOutcomeIssueComponent iss : op.getIssue()) {
@@ -91,7 +91,7 @@ public class ValidationEngineTests {
     }
     if (!org.hl7.fhir.validation.tests.utilities.TestUtilities.silent)
       System.out.println("Test102: Validate patient-example.xml in v1.0.2 version");
-    ValidationEngine ve = new ValidationEngine("hl7.fhir.r2.core#1.0.2", DEF_TX, null, FhirPublication.DSTU2, "1.0.2");
+    ValidationEngine ve = new ValidationEngine("hl7.fhir.r2.core#1.0.2", DEF_TX, null, FhirPublication.DSTU2, "1.0.2", "fhir/test-cases");
     ve.setNoInvariantChecks(true);
     OperationOutcome op = ve.validate(FhirFormat.XML, TestingUtilities.loadTestResourceStream("validator", "patient102.xml"), null);
     if (!TestUtilities.silent)
@@ -116,7 +116,7 @@ public class ValidationEngineTests {
     }
     if (!TestUtilities.silent)
       System.out.println("TestObs102: Validate patient-example.xml in v1.0.2 version");
-    ValidationEngine ve = new ValidationEngine("hl7.fhir.r2.core#1.0.2", DEF_TX, null, FhirPublication.DSTU2, "1.0.2");
+    ValidationEngine ve = new ValidationEngine("hl7.fhir.r2.core#1.0.2", DEF_TX, null, FhirPublication.DSTU2, "1.0.2", "fhir/test-cases");
     ve.setNoInvariantChecks(true);
     OperationOutcome op = ve.validate(FhirFormat.JSON, TestingUtilities.loadTestResourceStream("validator", "observation102.json"), null);
     if (!TestUtilities.silent)
@@ -138,7 +138,7 @@ public class ValidationEngineTests {
   public void test301() throws Exception {
     if (!TestUtilities.silent)
       System.out.println("Test301: Validate observation301.xml against Core");
-    ValidationEngine ve = new ValidationEngine("hl7.fhir.r3.core#3.0.2", DEF_TX, null, FhirPublication.STU3, "3.0.2");
+    ValidationEngine ve = new ValidationEngine("hl7.fhir.r3.core#3.0.2", DEF_TX, null, FhirPublication.STU3, "3.0.2", "fhir/test-cases");
     if (!TestUtilities.silent)
       System.out.println("  .. load USCore");
     OperationOutcome op = ve.validate(FhirFormat.XML, TestingUtilities.loadTestResourceStream("validator", "observation301.xml"), null);
@@ -157,7 +157,7 @@ public class ValidationEngineTests {
   public void test301USCore() throws Exception {
     if (!TestUtilities.silent)
       System.out.println("Test301USCore: Validate patient300.xml against US-Core");
-    ValidationEngine ve = new ValidationEngine("hl7.fhir.r3.core#3.0.2", DEF_TX, null, FhirPublication.STU3, "3.0.2");
+    ValidationEngine ve = new ValidationEngine("hl7.fhir.r3.core#3.0.2", DEF_TX, null, FhirPublication.STU3, "3.0.2", "fhir/test-cases");
     IgLoader igLoader = new IgLoader(ve.getPcm(), ve.getContext(), ve.getVersion(), true);
     if (!TestUtilities.silent)
       System.out.println("  .. load USCore");
diff --git a/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/tests/ValidationTests.java b/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/tests/ValidationTests.java
index 482719191..bab3a5c34 100644
--- a/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/tests/ValidationTests.java
+++ b/org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/tests/ValidationTests.java
@@ -111,8 +111,6 @@ public class ValidationTests implements IEvaluationContext, IValidatorResourceFe
   private String version;
   private String name;
 
-  private static final String DEF_TX = "http://tx.fhir.org";
-//  private static final String DEF_TX = "http://local.fhir.org:960";
   private static Map<String, ValidationEngine> ve = new HashMap<>();
   private static ValidationEngine vCurr;
   private static IgLoader igLoader;
@@ -143,19 +141,20 @@ public class ValidationTests implements IEvaluationContext, IValidatorResourceFe
     version = VersionUtilities.getMajMin(version);
     if (!ve.containsKey(version)) {
       if (version.startsWith("5.0"))
-        ve.put(version, new ValidationEngine("hl7.fhir.r5.core#4.5.0", DEF_TX, txLog, FhirPublication.R5, true, "4.5.0"));
+        ve.put(version, new ValidationEngine("hl7.fhir.r5.core#4.5.0", ValidationEngineTests.DEF_TX, txLog, FhirPublication.R5, true, "4.5.0", "fhir/test-cases"));
       else if (version.startsWith("3.0"))
-        ve.put(version, new ValidationEngine("hl7.fhir.r3.core#3.0.2", DEF_TX, txLog, FhirPublication.STU3, true, "3.0.2"));
+        ve.put(version, new ValidationEngine("hl7.fhir.r3.core#3.0.2", ValidationEngineTests.DEF_TX, txLog, FhirPublication.STU3, true, "3.0.2", "fhir/test-cases"));
       else if (version.startsWith("4.0"))
-        ve.put(version, new ValidationEngine("hl7.fhir.r4.core#4.0.1", DEF_TX, txLog, FhirPublication.R4, true, "4.0.1"));
+        ve.put(version, new ValidationEngine("hl7.fhir.r4.core#4.0.1", ValidationEngineTests.DEF_TX, txLog, FhirPublication.R4, true, "4.0.1", "fhir/test-cases"));
       else if (version.startsWith("1.0"))
-        ve.put(version, new ValidationEngine("hl7.fhir.r2.core#1.0.2", DEF_TX, txLog, FhirPublication.DSTU2, true, "1.0.2"));
+        ve.put(version, new ValidationEngine("hl7.fhir.r2.core#1.0.2", ValidationEngineTests.DEF_TX, txLog, FhirPublication.DSTU2, true, "1.0.2", "fhir/test-cases"));
       else if (version.startsWith("1.4"))
-        ve.put(version, new ValidationEngine("hl7.fhir.r2b.core#1.4.0", DEF_TX, txLog, FhirPublication.DSTU2016May, true, "1.4.0"));
+        ve.put(version, new ValidationEngine("hl7.fhir.r2b.core#1.4.0", ValidationEngineTests.DEF_TX, txLog, FhirPublication.DSTU2016May, true, "1.4.0", "fhir/test-cases"));
       else
         throw new Exception("unknown version " + version);
     }
     vCurr = ve.get(version);
+    vCurr.getContext().setUserAgent("fhir/test-cases");
     igLoader = new IgLoader(vCurr.getPcm(), vCurr.getContext(), vCurr.getVersion(), true);
     if (TestingUtilities.fcontexts == null) {
       TestingUtilities.fcontexts = new HashMap<>();