diff --git a/s3-bucket-list b/s3-bucket-list
index 352e65e..6d20670 100755
--- a/s3-bucket-list
+++ b/s3-bucket-list
@@ -3,12 +3,16 @@ import html
 import http.client
 import json
 import os
+import re
 import shlex
 import ssl
 import sys
 import urllib.parse
 
 
+RESPONSE_PATTERN = re.compile(r'''^<\?xml version=(["'])1\.0\1 encoding=(["'])UTF-8\2\?>''' '\n?' r'''<ListBucketResult xmlns=(["'])http://(?:s3\.amazonaws\.com/doc/2006-03-01/|doc\.s3\.amazonaws\.com/2006-03-01)\3>'''.encode('ascii'))
+
+
 # Arguments
 i = 1
 withListUrls = False
@@ -79,7 +83,7 @@ while True:
 			break
 		attempt += 1
 		continue
-	if not body.startswith(b'<?xml version="1.0" encoding="UTF-8"?>\n<ListBucketResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/">') and not body.startswith(b"<?xml version='1.0' encoding='UTF-8'?><ListBucketResult xmlns='http://doc.s3.amazonaws.com/2006-03-01'>"):
+	if not RESPONSE_PATTERN.match(body):
 		raise RuntimeError(f'Invalid body: {body[:200]}...')
 
 	if b'<Marker></Marker>' in body[:200] and 'marker' in params: