diff --git a/vcsserver/hgcompat.py b/vcsserver/hgcompat.py
--- a/vcsserver/hgcompat.py
+++ b/vcsserver/hgcompat.py
@@ -36,6 +36,7 @@ from mercurial import unionrepo
 from mercurial import localrepo
 from mercurial import merge as hg_merge
 from mercurial import subrepo
+from mercurial import subrepoutil
 from mercurial import tags as hg_tag
 
 from mercurial.commands import clone, nullid, pull
diff --git a/vcsserver/hgpatches.py b/vcsserver/hgpatches.py
--- a/vcsserver/hgpatches.py
+++ b/vcsserver/hgpatches.py
@@ -62,7 +62,7 @@ def _dynamic_capabilities_wrapper(lfprot
 
 def patch_subrepo_type_mapping():
     from collections import defaultdict
-    from hgcompat import subrepo
+    from hgcompat import subrepo, subrepoutil
     from vcsserver.exceptions import SubrepoMergeException
 
     class NoOpSubrepo(subrepo.abstractsubrepo):
@@ -97,7 +97,7 @@ def patch_subrepo_type_mapping():
         def basestate(self):
             """current working directory base state, disregarding .hgsubstate
             state and working directory modifications"""
-            substate = subrepo.state(self._ctx, self.ui)
+            substate = subrepoutil.state(self._ctx, self.ui)
             file_system_path, rev, repotype = substate.get(self._path)
             return rev