--- a/mercurial/context.py	Thu Aug 03 14:08:39 2017 +0200
+++ b/mercurial/context.py	Fri Aug 04 19:27:39 2017 +0200
@@ -211,7 +211,7 @@
 
     def orphan(self):
         """True if the changeset is not obsolete but it's ancestor are"""
-        return self.rev() in obsmod.getrevs(self._repo, 'unstable')
+        return self.rev() in obsmod.getrevs(self._repo, 'orphan')
 
     def bumped(self):
         msg = ("'context.bumped' is deprecated, "