diff --git a/acme4j-client/src/main/java/org/shredzone/acme4j/connector/DefaultConnection.java b/acme4j-client/src/main/java/org/shredzone/acme4j/connector/DefaultConnection.java
index f4165804..7a8016eb 100644
--- a/acme4j-client/src/main/java/org/shredzone/acme4j/connector/DefaultConnection.java
+++ b/acme4j-client/src/main/java/org/shredzone/acme4j/connector/DefaultConnection.java
@@ -138,7 +138,7 @@ public class DefaultConnection implements Connection {
             conn.setRequestProperty("Accept", "application/json");
             conn.setRequestProperty("Accept-Charset", "utf-8");
             conn.setRequestProperty("Accept-Language", session.getLocale().toLanguageTag());
-            conn.setRequestProperty("Content-Type", "application/json");
+            conn.setRequestProperty("Content-Type", "application/jose+json");
             conn.setDoOutput(true);
 
             final PublicJsonWebKey jwk = PublicJsonWebKey.Factory.newPublicJwk(keypair.getPublic());
@@ -146,6 +146,7 @@ public class DefaultConnection implements Connection {
             JsonWebSignature jws = new JsonWebSignature();
             jws.setPayload(claims.toString());
             jws.getHeaders().setObjectHeaderValue("nonce", Base64Url.encode(session.getNonce()));
+            jws.getHeaders().setObjectHeaderValue("url", uri);
             jws.getHeaders().setJwkHeaderValue("jwk", jwk);
             jws.setAlgorithmHeaderValue(SignatureUtils.keyAlgorithm(jwk));
             jws.setKey(keypair.getPrivate());
diff --git a/acme4j-client/src/test/java/org/shredzone/acme4j/connector/DefaultConnectionTest.java b/acme4j-client/src/test/java/org/shredzone/acme4j/connector/DefaultConnectionTest.java
index 7ebf79a2..f7eaad93 100644
--- a/acme4j-client/src/test/java/org/shredzone/acme4j/connector/DefaultConnectionTest.java
+++ b/acme4j-client/src/test/java/org/shredzone/acme4j/connector/DefaultConnectionTest.java
@@ -451,7 +451,7 @@ public class DefaultConnectionTest {
         verify(mockUrlConnection).setRequestMethod("POST");
         verify(mockUrlConnection).setRequestProperty("Accept", "application/json");
         verify(mockUrlConnection).setRequestProperty("Accept-Charset", "utf-8");
-        verify(mockUrlConnection).setRequestProperty("Content-Type", "application/json");
+        verify(mockUrlConnection).setRequestProperty("Content-Type", "application/jose+json");
         verify(mockUrlConnection).setDoOutput(true);
         verify(mockUrlConnection).setFixedLengthStreamingMode(outputStream.toByteArray().length);
         verify(mockUrlConnection).getOutputStream();
@@ -467,6 +467,7 @@ public class DefaultConnectionTest {
         StringBuilder expectedHeader = new StringBuilder();
         expectedHeader.append('{');
         expectedHeader.append("\"nonce\":\"").append(Base64Url.encode(nonce1)).append("\",");
+        expectedHeader.append("\"url\":\"").append(requestUri).append("\",");
         expectedHeader.append("\"alg\":\"RS256\",");
         expectedHeader.append("\"jwk\":{");
         expectedHeader.append("\"kty\":\"").append(TestUtils.KTY).append("\",");
@@ -474,7 +475,7 @@ public class DefaultConnectionTest {
         expectedHeader.append("\"n\":\"").append(TestUtils.N).append("\"");
         expectedHeader.append("}}");
 
-        assertThat(header, sameJSONAs(expectedHeader.toString()).allowingExtraUnexpectedFields());
+        assertThat(header, sameJSONAs(expectedHeader.toString()));
         assertThat(claims, sameJSONAs("{\"foo\":123,\"bar\":\"a-string\"}"));
         assertThat(signature, not(isEmptyOrNullString()));