diff -r 75abdd7f2568 roundup/cgi/templating.py
--- a/roundup/cgi/templating.py	Thu Jul 30 17:16:32 2026 -0400
+++ b/roundup/cgi/templating.py	Mon Aug 03 02:15:38 2026 +0000
@@ -3747,12 +3747,32 @@
             # backwards-compatibility
             raise AttributeError(name)
         if name not in self.client.instance.templating_utils:
+            # allow use of localReplace in templates allowing tracker
+            # admin to override using extensions mechanism - issue2559030.
+            if name == "localReplace":
+                return self.__localReplace
             raise AttributeError(name)
         return self.client.instance.templating_utils[name]
 
     def keywords_expressions(self, request):
         return render_keywords_expression_editor(request)
 
+    @staticmethod
+    def __localReplace(message):
+        """Default no-op for localReplace.
+
+           Override with real definition in extensions.
+
+           This allows templates to ship with localReplace(....)
+           and have an:
+
+               instance.registerUtil('localReplace', local_replace)
+
+           define localReplace with the same call signature (i.e. no self)
+           in the extension definition.
+        """
+        return message
+
     def html_calendar(self, request):
         """Generate a HTML calendar.