diff --git a/radicale/xmlutils.py b/radicale/xmlutils.py
index e22511ea..c65e9b35 100644
--- a/radicale/xmlutils.py
+++ b/radicale/xmlutils.py
@@ -34,20 +34,15 @@ import xml.etree.ElementTree as ET
 from radicale import client, config, ical
 
 
-# TODO: This is a well-known and accepted hack for ET to avoid ET from renaming
-#       namespaces, which is accepted in XML norm but often not in XML
-#       readers. Is there another clean solution to force namespaces?
-PROTECTED_NAMESPACES = {
+NAMESPACES = {
     "C": "urn:ietf:params:xml:ns:caldav",
     "D": "DAV:",
     "CS": "http://calendarserver.org/ns/"}
-for key, value in PROTECTED_NAMESPACES.items():
-    ET._namespace_map[value] = key
 
 
 def _tag(short_name, local):
     """Get XML Clark notation {uri(``short_name``)}``local``."""
-    return "{%s}%s" % (PROTECTED_NAMESPACES[short_name], local)
+    return "{%s}%s" % (NAMESPACES[short_name], local)
 
 
 def _response(code):