diff --git a/gramps/gen/lib/calendar.py b/gramps/gen/lib/calendar.py
index 7d963fa2d..bb0fd8ff1 100644
--- a/gramps/gen/lib/calendar.py
+++ b/gramps/gen/lib/calendar.py
@@ -23,7 +23,7 @@
 """
 Provide calendar to sdn (serial date number) conversion.
 """
-from __future__ import division
+from __future__ import division, print_function
 #-------------------------------------------------------------------------
 #
 # Python modules
@@ -261,7 +261,7 @@ def hebrew_sdn(year, month, day):
     return sdn + _HBR_SDN_OFFSET
 
 def hebrew_ymd(sdn):
-    """Convert an SDN number to a Julian calendar date."""
+    """Convert an SDN number to a Hebrew calendar date."""
         
     input_day = sdn - _HBR_SDN_OFFSET
 
@@ -573,3 +573,14 @@ def swedish_ymd(sdn):
         return gregorian_ymd(sdn)
     else:
         return julian_ymd(sdn)
+
+try:
+    import sdn
+    
+    hebrew_ymd = sdn.SdnToJewish # Fix bug# 7066
+    hebrew_sdn = sdn.JewishToSdn 
+    #TODO maybe alias the other local invented wheels to Calendar convertors
+except ImportError:
+    import sys
+    print("No sdn module. Install Calendar with pypi."
+            "hebrew_sdn has a known bug# 7066!!!", file=sys.stderr)
diff --git a/gramps/grampsapp.py b/gramps/grampsapp.py
index 34f72ab40..1255962bb 100644
--- a/gramps/grampsapp.py
+++ b/gramps/grampsapp.py
@@ -320,6 +320,12 @@ def show_settings():
     except:
         gsversion_str = 'Ghostscript not in system PATH'
 
+    try:
+        import sdn
+        sdn_str = sdn.__version__
+    except ImportError:
+        sdn_str = 'not found'
+
     os_path = os.environ.get('PATH','not set')
     os_path = os_path.split(os.pathsep)
     
@@ -342,6 +348,7 @@ def show_settings():
     print (' GExiv2    : %s' % gexiv2_str)
     print (' ICU       : %s' % icu_str)
     print (' PyICU     : %s' % pyicu_str)
+    print (' sdn       : %s' % sdn_str)
     print (' o.s.      : %s' % sys.platform)
     if kernel:
         print (' kernel    : %s' % kernel)