diff --git a/src/test/java/com/bandwidth/sdk/unit/api/ConferencesApiTest.java b/src/test/java/com/bandwidth/sdk/unit/api/ConferencesApiTest.java
index 77ebefa2..cf3b33d3 100644
--- a/src/test/java/com/bandwidth/sdk/unit/api/ConferencesApiTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/api/ConferencesApiTest.java
@@ -88,7 +88,7 @@ public void testGetConferenceMember() throws ApiException {
         assertThat(response.getData(), instanceOf(ConferenceMember.class));
         assertThat(response.getData().getCallId().length(), is(47));
         assertThat(response.getData().getConferenceId().length(), is(50));
-        assertThat(response.getData().getMemberUrl(), instanceOf(String.class)); // should be a URI
+        assertThat(response.getData().getMemberUrl(), instanceOf(URI.class));
         assertThat(response.getData().getMute(), instanceOf(Boolean.class));
         assertThat(response.getData().getHold(), instanceOf(Boolean.class));
         assertThat(response.getData().getCallIdsToCoach(), instanceOf(List.class));
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/AnswerCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/AnswerCallbackTest.java
index d56c7cd3..e8655730 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/AnswerCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/AnswerCallbackTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.time.OffsetDateTime;
 import com.bandwidth.sdk.model.AnswerCallback;
 import com.bandwidth.sdk.model.CallDirectionEnum;
@@ -35,7 +36,7 @@ public class AnswerCallbackTest {
             .to("to")
             .direction(CallDirectionEnum.INBOUND)
             .callId("callId")
-            .callUrl("callUrl")
+            .callUrl(URI.create("https://bandwidth.com"))
             .enqueuedTime(OffsetDateTime.now())
             .startTime(OffsetDateTime.now())
             .answerTime(OffsetDateTime.now())
@@ -121,7 +122,7 @@ public void callIdTest() {
      */
     @Test
     public void callUrlTest() {
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/BridgeCompleteCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/BridgeCompleteCallbackTest.java
index bd7da5a3..13cf0139 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/BridgeCompleteCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/BridgeCompleteCallbackTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.time.OffsetDateTime;
 import com.bandwidth.sdk.model.BridgeCompleteCallback;
 import com.bandwidth.sdk.model.CallDirectionEnum;
@@ -34,7 +35,7 @@ public class BridgeCompleteCallbackTest {
             .to("to")
             .direction(CallDirectionEnum.INBOUND)
             .callId("callId")
-            .callUrl("callUrl")
+            .callUrl(URI.create("https://bandwidth.com"))
             .enqueuedTime(OffsetDateTime.now())
             .startTime(OffsetDateTime.now())
             .answerTime(OffsetDateTime.now())
@@ -120,7 +121,7 @@ public void callIdTest() {
      */
     @Test
     public void callUrlTest() {
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/BridgeTargetCompleteCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/BridgeTargetCompleteCallbackTest.java
index 97a062cd..9a52ef97 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/BridgeTargetCompleteCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/BridgeTargetCompleteCallbackTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.time.OffsetDateTime;
 import com.bandwidth.sdk.model.BridgeTargetCompleteCallback;
 import com.bandwidth.sdk.model.CallDirectionEnum;
@@ -34,7 +35,7 @@ public class BridgeTargetCompleteCallbackTest {
             .to("to")
             .direction(CallDirectionEnum.INBOUND)
             .callId("callId")
-            .callUrl("callUrl")
+            .callUrl(URI.create("https://bandwidth.com"))
             .enqueuedTime(OffsetDateTime.now())
             .startTime(OffsetDateTime.now())
             .answerTime(OffsetDateTime.now())
@@ -117,7 +118,7 @@ public void callIdTest() {
      */
     @Test
     public void callUrlTest() {
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/ConferenceMemberTest.java b/src/test/java/com/bandwidth/sdk/unit/models/ConferenceMemberTest.java
index 3fb8e288..c9abbf64 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/ConferenceMemberTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/ConferenceMemberTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.util.List;
 import java.util.Arrays;
 import java.util.ArrayList;
@@ -29,7 +30,7 @@ public class ConferenceMemberTest {
     private final ConferenceMember model = new ConferenceMember()
             .callId("callId")
             .conferenceId("conferenceId")
-            .memberUrl("memberUrl")
+            .memberUrl(URI.create("https://bandwidth.com"))
             .mute(true)
             .hold(true)
             .callIdsToCoach(new ArrayList<String>(Arrays.asList("callIdsToCoach")));
@@ -63,7 +64,7 @@ public void conferenceIdTest() {
      */
     @Test
     public void memberUrlTest() {
-        assertThat(model.getMemberUrl(), instanceOf(String.class));
+        assertThat(model.getMemberUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/DisconnectCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/DisconnectCallbackTest.java
index 15056651..5d05e41f 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/DisconnectCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/DisconnectCallbackTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.time.OffsetDateTime;
 import com.bandwidth.sdk.model.DisconnectCallback;
 import com.bandwidth.sdk.model.CallDirectionEnum;
@@ -34,7 +35,7 @@ public class DisconnectCallbackTest {
             .to("to")
             .callId("callId")
             .direction(CallDirectionEnum.INBOUND)
-            .callUrl("callUrl")
+            .callUrl(URI.create("https://bandwidth.com"))
             .enqueuedTime(OffsetDateTime.now())
             .startTime(OffsetDateTime.now())
             .answerTime(OffsetDateTime.now())
@@ -121,7 +122,7 @@ public void directionTest() {
      */
     @Test
     public void callUrlTest() {
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/DtmfCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/DtmfCallbackTest.java
index 1ec95d38..a5925616 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/DtmfCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/DtmfCallbackTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.time.OffsetDateTime;
 import com.bandwidth.sdk.model.DtmfCallback;
 import com.bandwidth.sdk.model.CallDirectionEnum;
@@ -35,7 +36,7 @@ public class DtmfCallbackTest {
             .callId("callId")
             .direction(CallDirectionEnum.INBOUND)
             .digit("digit")
-            .callUrl("callUrl")
+            .callUrl(URI.create("https://bandwidth.com"))
             .enqueuedTime(OffsetDateTime.now())
             .startTime(OffsetDateTime.now())
             .answerTime(OffsetDateTime.now())
@@ -129,7 +130,7 @@ public void digitTest() {
      */
     @Test
     public void callUrlTest() {
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/GatherCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/GatherCallbackTest.java
index 31195da5..056968c2 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/GatherCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/GatherCallbackTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.time.OffsetDateTime;
 import com.bandwidth.sdk.model.GatherCallback;
 import com.bandwidth.sdk.model.CallDirectionEnum;
@@ -35,7 +36,7 @@ public class GatherCallbackTest {
             .direction(CallDirectionEnum.INBOUND)
             .callId("callId")
             .digits("digits")
-            .callUrl("callUrl")
+            .callUrl(URI.create("https://bandwidth.com"))
             .enqueuedTime(OffsetDateTime.now())
             .startTime(OffsetDateTime.now())
             .answerTime(OffsetDateTime.now())
@@ -130,7 +131,7 @@ public void digitsTest() {
      */
     @Test
     public void callUrlTest() {
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/InitiateCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/InitiateCallbackTest.java
index d92dac83..b8da33ec 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/InitiateCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/InitiateCallbackTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.time.OffsetDateTime;
 import com.bandwidth.sdk.model.InitiateCallback;
 import com.bandwidth.sdk.model.Diversion;
@@ -36,7 +37,7 @@ public class InitiateCallbackTest {
             .to("to")
             .direction(CallDirectionEnum.INBOUND)
             .callId("callId")
-            .callUrl("callUrl")
+            .callUrl(URI.create("https://bandwidth.com"))
             .startTime(OffsetDateTime.now())
             .diversion(new Diversion())
             .stirShaken(new StirShaken());
@@ -118,7 +119,7 @@ public void callIdTest() {
      */
     @Test
     public void callUrlTest() {
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/MachineDetectionCompleteCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/MachineDetectionCompleteCallbackTest.java
index 96393350..bf333c2f 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/MachineDetectionCompleteCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/MachineDetectionCompleteCallbackTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.time.OffsetDateTime;
 import com.bandwidth.sdk.model.MachineDetectionCompleteCallback;
 import com.bandwidth.sdk.model.CallDirectionEnum;
@@ -35,7 +36,7 @@ public class MachineDetectionCompleteCallbackTest {
             .to("to")
             .direction(CallDirectionEnum.INBOUND)
             .callId("callId")
-            .callUrl("callUrl")
+            .callUrl(URI.create("https://bandwidth.com"))
             .enqueuedTime(OffsetDateTime.now())
             .startTime(OffsetDateTime.now())
             .answerTime(OffsetDateTime.now())
@@ -119,7 +120,7 @@ public void callIdTest() {
      */
     @Test
     public void callUrlTest() {
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/RecordingAvailableCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/RecordingAvailableCallbackTest.java
index 72d9c2ed..8676243f 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/RecordingAvailableCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/RecordingAvailableCallbackTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.net.URI;
 import java.time.OffsetDateTime;
 import com.bandwidth.sdk.model.RecordingAvailableCallback;
@@ -36,7 +37,7 @@ public class RecordingAvailableCallbackTest {
             .to("to")
             .direction(CallDirectionEnum.INBOUND)
             .callId("callId")
-            .callUrl("callUrl")
+            .callUrl(URI.create("https://bandwidth.com"))
             .parentCallId("parentCallId")
             .recordingId("recordingId")
             .mediaUrl(URI.create("https://example.com"))
@@ -128,7 +129,7 @@ public void callIdTest() {
      */
     @Test
     public void callUrlTest() {
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/RecordingCompleteCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/RecordingCompleteCallbackTest.java
index b9444b42..5a176b86 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/RecordingCompleteCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/RecordingCompleteCallbackTest.java
@@ -36,7 +36,7 @@ public class RecordingCompleteCallbackTest {
             .to("to")
             .direction(CallDirectionEnum.INBOUND)
             .callId("callId")
-            .callUrl("https://bandwidth.com") // should be a URI, need to update the spec
+            .callUrl(URI.create("https://bandwidth.com"))
             .parentCallId("parentCallId")
             .recordingId("recordingId")
             .mediaUrl(URI.create("https://bandwidth.com"))
@@ -129,7 +129,7 @@ public void callIdTest() {
     @Test
     public void callUrlTest() {
         // assertThat(model.getCallUrl(), instanceOf(URI.class));
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/RedirectCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/RedirectCallbackTest.java
index 6918c7ed..a04f6662 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/RedirectCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/RedirectCallbackTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.time.OffsetDateTime;
 import com.bandwidth.sdk.model.RedirectCallback;
 import com.bandwidth.sdk.model.CallDirectionEnum;
@@ -34,7 +35,7 @@ public class RedirectCallbackTest {
             .to("to")
             .direction(CallDirectionEnum.INBOUND)
             .callId("callId")
-            .callUrl("callUrl")
+            .callUrl(URI.create("https://bandwidth.com"))
             .parentCallId("parentCallId")
             .enqueuedTime(OffsetDateTime.now())
             .startTime(OffsetDateTime.now())
@@ -120,7 +121,7 @@ public void callIdTest() {
      */
     @Test
     public void callUrlTest() {
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/TranscriptionAvailableCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/TranscriptionAvailableCallbackTest.java
index 2af84d6f..eb59b826 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/TranscriptionAvailableCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/TranscriptionAvailableCallbackTest.java
@@ -37,7 +37,7 @@ public class TranscriptionAvailableCallbackTest {
             .to("to")
             .direction(CallDirectionEnum.INBOUND)
             .callId("callId") // should be URI
-            .callUrl("https://example.com")
+            .callUrl(URI.create("https://bandwidth.com"))
             .mediaUrl(URI.create("https://example.com"))
             .parentCallId("parentCallId")
             .recordingId("recordingId")
@@ -129,7 +129,7 @@ public void callIdTest() {
     @Test
     public void callUrlTest() {
         // assertThat(model.getCallUrl(), instanceOf(URI.class));
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/TransferAnswerCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/TransferAnswerCallbackTest.java
index acec0148..1394db0e 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/TransferAnswerCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/TransferAnswerCallbackTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.time.OffsetDateTime;
 import com.bandwidth.sdk.model.TransferAnswerCallback;
 import com.bandwidth.sdk.model.CallDirectionEnum;
@@ -34,7 +35,7 @@ public class TransferAnswerCallbackTest {
             .to("to")
             .direction(CallDirectionEnum.INBOUND)
             .callId("callId")
-            .callUrl("callUrl") // Should be URI
+            .callUrl(URI.create("https://bandwidth.com")) // Should be URI
             .enqueuedTime(OffsetDateTime.now())
             .startTime(OffsetDateTime.now())
             .answerTime(OffsetDateTime.now())
@@ -119,7 +120,7 @@ public void callIdTest() {
      */
     @Test
     public void callUrlTest() {
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/TransferCompleteCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/TransferCompleteCallbackTest.java
index ed50bbd1..db116516 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/TransferCompleteCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/TransferCompleteCallbackTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.time.OffsetDateTime;
 import com.bandwidth.sdk.model.TransferCompleteCallback;
 import com.bandwidth.sdk.model.CallDirectionEnum;
@@ -34,7 +35,7 @@ public class TransferCompleteCallbackTest {
             .to("to")
             .direction(CallDirectionEnum.INBOUND)
             .callId("callId")
-            .callUrl("callUrl") // should be uri
+            .callUrl(URI.create("https://bandwidth.com")) // should be uri
             .enqueuedTime(OffsetDateTime.now())
             .startTime(OffsetDateTime.now())
             .answerTime(OffsetDateTime.now())
@@ -122,7 +123,7 @@ public void callIdTest() {
      */
     @Test
     public void callUrlTest() {
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/TransferDisconnectCallbackTest.java b/src/test/java/com/bandwidth/sdk/unit/models/TransferDisconnectCallbackTest.java
index 38c111e8..7eb52e51 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/TransferDisconnectCallbackTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/TransferDisconnectCallbackTest.java
@@ -14,6 +14,7 @@
 
 import org.junit.jupiter.api.Test;
 
+import java.net.URI;
 import java.time.OffsetDateTime;
 import com.bandwidth.sdk.model.TransferDisconnectCallback;
 import com.bandwidth.sdk.model.CallDirectionEnum;
@@ -34,7 +35,7 @@ public class TransferDisconnectCallbackTest {
             .to("to")
             .direction(CallDirectionEnum.INBOUND)
             .callId("callId")
-            .callUrl("callUrl")
+            .callUrl(URI.create("https://bandwidth.com"))
             .parentCallId("parentCallId")
             .enqueuedTime(OffsetDateTime.now())
             .startTime(OffsetDateTime.now())
@@ -124,7 +125,7 @@ public void callIdTest() {
      */
     @Test
     public void callUrlTest() {
-        assertThat(model.getCallUrl(), instanceOf(String.class));
+        assertThat(model.getCallUrl(), instanceOf(URI.class));
     }
 
     /**
diff --git a/src/test/java/com/bandwidth/sdk/unit/models/bxml/TransferVerbTest.java b/src/test/java/com/bandwidth/sdk/unit/models/bxml/TransferVerbTest.java
index 682b665d..301fd75a 100644
--- a/src/test/java/com/bandwidth/sdk/unit/models/bxml/TransferVerbTest.java
+++ b/src/test/java/com/bandwidth/sdk/unit/models/bxml/TransferVerbTest.java
@@ -58,7 +58,7 @@ public class TransferVerbTest {
         public void transferVerbWorks() throws JAXBException {
                 JAXBContext jaxbContext = JAXBContext.newInstance(Bxml.class);
                 String expectedSipUriBxml = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><Bxml><Transfer transferCallerId=\"+19195554321\" callTimeout=\"15.0\" transferCompleteMethod=\"POST\" transferCompleteFallbackMethod=\"POST\" tag=\"test\" diversionTreatment=\"none\" diversionReason=\"unknown\"><SipUri uui=\"test\" transferAnswerUrl=\"https://example.com/webhooks/transfer_answer\" transferAnswerMethod=\"POST\" transferAnswerFallbackMethod=\"POST\" transferDisconnectMethod=\"POST\" tag=\"test\">sip@bw.com</SipUri></Transfer></Bxml>";
-                String expectedPhoneNumberBxml = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><Bxml><Transfer transferCallerId=\"+19195554321\" transferCallerDisplayName=\"Clark Kent\" callTimeout=\"15.0\" transferCompleteMethod=\"POST\" transferCompleteFallbackMethod=\"POST\" tag=\"test\" diversionTreatment=\"none\" diversionReason=\"unknown\"><PhoneNumber transferAnswerUrl=\"https://example.com/webhooks/transfer_answer\" transferAnswerMethod=\"POST\" transferAnswerFallbackMethod=\"POST\" transferDisconnectMethod=\"POST\" tag=\"test\">+19195551234</PhoneNumber></Transfer></Bxml>"; //
+                String expectedPhoneNumberBxml = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><Bxml><Transfer transferCallerId=\"+19195554321\" transferCallerDisplayName=\"Clark Kent\" callTimeout=\"15.0\" transferCompleteMethod=\"POST\" transferCompleteFallbackMethod=\"POST\" tag=\"test\" diversionTreatment=\"none\" diversionReason=\"unknown\"><PhoneNumber transferAnswerUrl=\"https://example.com/webhooks/transfer_answer\" transferAnswerMethod=\"POST\" transferAnswerFallbackMethod=\"POST\" transferDisconnectMethod=\"POST\" tag=\"test\">+19195551234</PhoneNumber></Transfer></Bxml>";
 
                 assertThat(new Bxml().with(transfer1).toBxml(jaxbContext), is(expectedSipUriBxml));
                 assertThat(new Bxml().with(transfer2).toBxml(jaxbContext), is(expectedPhoneNumberBxml));