--- a/hgext3rd/evolve/obshistory.py	Fri Oct 20 18:19:01 2017 +0200
+++ b/hgext3rd/evolve/obshistory.py	Fri Oct 20 18:50:26 2017 +0200
@@ -17,12 +17,17 @@
     mdiff,
     patch,
     obsolete,
-    obsutil,
     node as nodemod,
     scmutil,
     util,
 )
 
+try:
+    from mercurial import obsutil
+    obsutil.marker
+except ImportError:
+    obsutil = None
+
 from mercurial.i18n import _
 
 from . import (