diff --git a/hgext/narrow/narrowwirepeer.py b/hgext/narrow/narrowwirepeer.py
--- a/hgext/narrow/narrowwirepeer.py
+++ b/hgext/narrow/narrowwirepeer.py
@@ -17,8 +17,8 @@
     wireprotov1server,
 )
 
-NARROWCAP = 'narrow'
-ELLIPSESCAP = 'ellipses'
+NARROWCAP = 'exp-narrow-1'
+ELLIPSESCAP = 'exp-ellipses-1'
 
 def uisetup():
     def peersetup(ui, peer):
diff --git a/tests/test-narrow-clone-non-narrow-server.t b/tests/test-narrow-clone-non-narrow-server.t
--- a/tests/test-narrow-clone-non-narrow-server.t
+++ b/tests/test-narrow-clone-non-narrow-server.t
@@ -33,7 +33,7 @@
   $ echo hello | hg -R . serve --stdio | \
   >   $PYTHON unquote.py | grep narrow
   narrow=v0
-  rev-branch-cache changegroupsubset getbundle known lookup narrow protocaps pushkey streamreqs=generaldelta,revlogv1 unbundle=HG10GZ,HG10BZ,HG10UN unbundlehash
+  rev-branch-cache changegroupsubset exp-narrow-1 getbundle known lookup protocaps pushkey streamreqs=generaldelta,revlogv1 unbundle=HG10GZ,HG10BZ,HG10UN unbundlehash
 
   $ cd ..