diff --git a/jetty-http/src/main/java/org/eclipse/jetty/http/HttpParser.java b/jetty-http/src/main/java/org/eclipse/jetty/http/HttpParser.java
index 4f34c27075b4..e6da0a2d7364 100644
--- a/jetty-http/src/main/java/org/eclipse/jetty/http/HttpParser.java
+++ b/jetty-http/src/main/java/org/eclipse/jetty/http/HttpParser.java
@@ -766,7 +766,7 @@ private boolean parseLine(ByteBuffer buffer)
                         case LF:
                             // HTTP/0.9
                             if (complianceViolation(HttpComplianceSection.NO_HTTP_0_9, "No request version"))
-                                throw new BadMessageException("HTTP/0.9 not supported");
+                                throw new BadMessageException(HttpStatus.HTTP_VERSION_NOT_SUPPORTED_505, "HTTP/0.9 not supported");
                             _requestHandler.startRequest(_methodString, _uri.toString(), HttpVersion.HTTP_0_9);
                             setState(State.CONTENT);
                             _endOfContent = EndOfContent.NO_CONTENT;
@@ -942,10 +942,10 @@ else if (n == HttpTokens.LINE_FEED)
     private void checkVersion()
     {
         if (_version == null)
-            throw new BadMessageException(HttpStatus.BAD_REQUEST_400, "Unknown Version");
+            throw new BadMessageException(HttpStatus.HTTP_VERSION_NOT_SUPPORTED_505, "Unknown Version");
 
         if (_version.getVersion() < 10 || _version.getVersion() > 20)
-            throw new BadMessageException(HttpStatus.BAD_REQUEST_400, "Bad Version");
+            throw new BadMessageException(HttpStatus.HTTP_VERSION_NOT_SUPPORTED_505, "Unsupported Version");
     }
 
     private void parsedHeader()
diff --git a/jetty-server/src/test/java/org/eclipse/jetty/server/HttpConnectionTest.java b/jetty-server/src/test/java/org/eclipse/jetty/server/HttpConnectionTest.java
index 322823388d17..bf4dbe48da9d 100644
--- a/jetty-server/src/test/java/org/eclipse/jetty/server/HttpConnectionTest.java
+++ b/jetty-server/src/test/java/org/eclipse/jetty/server/HttpConnectionTest.java
@@ -158,12 +158,12 @@ public void testHttp09NoVersion() throws Exception
         connector.getConnectionFactory(HttpConnectionFactory.class).setHttpCompliance(HttpCompliance.RFC2616);
         String request = "GET / HTTP/0.9\r\n\r\n";
         String response = connector.getResponse(request);
-        assertThat(response, containsString("400 Bad Version"));
+        assertThat(response, containsString("505 Unsupported Version"));
 
         connector.getConnectionFactory(HttpConnectionFactory.class).setHttpCompliance(HttpCompliance.RFC7230);
         request = "GET / HTTP/0.9\r\n\r\n";
         response = connector.getResponse(request);
-        assertThat(response, containsString("400 Bad Version"));
+        assertThat(response, containsString("505 Unsupported Version"));
     }
 
     /**
diff --git a/jetty-server/src/test/java/org/eclipse/jetty/server/handler/NcsaRequestLogTest.java b/jetty-server/src/test/java/org/eclipse/jetty/server/handler/NcsaRequestLogTest.java
index b8fb6a799a31..4bd0699e4100 100644
--- a/jetty-server/src/test/java/org/eclipse/jetty/server/handler/NcsaRequestLogTest.java
+++ b/jetty-server/src/test/java/org/eclipse/jetty/server/handler/NcsaRequestLogTest.java
@@ -303,7 +303,7 @@ public void testBadVersion(String logType) throws Exception
         _connector.getResponse("METHOD /foo HTTP/9\n\n");
         String log = _entries.poll(5, TimeUnit.SECONDS);
         assertThat(log, containsString("\"- - -\""));
-        assertThat(log, containsString(" 400 "));
+        assertThat(log, containsString(" 505 "));
     }
 
     @ParameterizedTest()