diff --git a/mercurial/wireproto.py b/mercurial/wireproto.py
--- a/mercurial/wireproto.py
+++ b/mercurial/wireproto.py
@@ -707,7 +707,7 @@ commands = commanddict()
 # For version 2 transports.
 commandsv2 = commanddict()
 
-def wireprotocommand(name, args='', transportpolicy=POLICY_ALL,
+def wireprotocommand(name, args='', transportpolicy=POLICY_V1_ONLY,
                      permission='push'):
     """Decorator to declare a wire protocol command.
 
diff --git a/tests/wireprotohelpers.sh b/tests/wireprotohelpers.sh
--- a/tests/wireprotohelpers.sh
+++ b/tests/wireprotohelpers.sh
@@ -16,12 +16,22 @@ from mercurial import (
 )
 
 @wireproto.wireprotocommand('customreadonly', permission='pull')
-def customreadonly(repo, proto):
+def customreadonlyv1(repo, proto):
+    return wireprototypes.bytesresponse(b'customreadonly bytes response')
+
+@wireproto.wireprotocommand('customreadonly', permission='pull',
+                            transportpolicy=wireproto.POLICY_V2_ONLY)
+def customreadonlyv2(repo, proto):
     return wireprototypes.bytesresponse(b'customreadonly bytes response')
 
 @wireproto.wireprotocommand('customreadwrite', permission='push')
 def customreadwrite(repo, proto):
     return wireprototypes.bytesresponse(b'customreadwrite bytes response')
+
+@wireproto.wireprotocommand('customreadwrite', permission='push',
+                            transportpolicy=wireproto.POLICY_V2_ONLY)
+def customreadwritev2(repo, proto):
+    return wireprototypes.bytesresponse(b'customreadwrite bytes response')
 EOF
 
 cat >> $HGRCPATH << EOF