diff --git a/indra/lib/python/indra/util/llversion.py b/indra/lib/python/indra/util/llversion.py
index 770b861ddc1604e6dd2d133aa94513560c154455..c48ab679f4c62015305588175d2b059c4a61ab9f 100644
--- a/indra/lib/python/indra/util/llversion.py
+++ b/indra/lib/python/indra/util/llversion.py
@@ -1,7 +1,7 @@
 """@file llversion.py
 @brief Utility for parsing llcommon/llversion${server}.h
        for the version string and channel string
-       Utility that parses svn info for branch and revision
+       Utility that parses hg or svn info for branch and revision
 
 $LicenseInfo:firstyear=2006&license=mit$
 
@@ -79,8 +79,8 @@ def get_svn_status_matching(regular_expression):
     status, output = commands.getstatusoutput('svn info %s' % get_src_root())
     m = regular_expression.search(output)
     if not m:
-        print "Failed to parse svn info output, resultfollows:"
-        print output
+        print >> sys.stderr, "Failed to parse svn info output, result follows:"
+        print >> sys.stderr, output
         raise Exception, "No matching svn status in "+src_root
     return m.group(1)
 
@@ -92,4 +92,25 @@ def get_svn_revision():
     last_rev_re = re.compile('Last Changed Rev: (\d+)')
     return get_svn_status_matching(last_rev_re)
 
-
+def get_hg_repo():
+    status, output = commands.getstatusoutput('hg showconfig paths.default')
+    if status:
+        print >> sys.stderr, output
+        sys.exit(1)
+    if not output:
+        print >> sys.stderr, 'ERROR: cannot find repo we cloned from'
+        sys.exit(1)
+    return output
+
+def get_hg_changeset():
+    status, output = commands.getstatusoutput('hg id -i')
+    if status:
+        print >> sys.stderr, output
+        sys.exit(1)
+    return output
+
+def using_svn():
+    return os.path.isdir(os.path.join(get_src_root(), '.svn'))
+
+def using_hg():
+    return os.path.isdir(os.path.join(get_src_root(), '.hg'))
diff --git a/scripts/update_version_files.py b/scripts/update_version_files.py
index 9081941521709e01df401be093179d5a7017f32f..ee1ce69a15bb5d865f3f6c6a4e0a647e15b23b43 100755
--- a/scripts/update_version_files.py
+++ b/scripts/update_version_files.py
@@ -241,23 +241,17 @@ def main():
         if update_server:
             server_version = new_version
     else:
-        # Assume we're updating just the build number
-        cl = '%s info "%s"' % (svn, src_root)
-        status, output = _getstatusoutput(cl)
-        if verbose:
-            print
-            print "svn info output:"
-            print "----------------"
-            print output
-
-        branch_match = svn_branch_re.search(output)
-        revision_match = svn_revision_re.search(output)
-        if not branch_match or not revision_match:
-            print "Failed to execute svn info, output follows:"
-            print output
+
+        if llversion.using_svn():
+            revision = llversion.get_svn_revision()
+            branch = llversion.get_svn_branch()
+        elif llversion.using_hg():
+            revision = llversion.get_hg_changeset()
+            branch = llversion.get_hg_repo()
+        else:
+            print >>sys.stderr, "ERROR: could not determine revision and branch"
             return -1
-        branch = branch_match.group(1)
-        revision = revision_match.group(1)
+        
         if skip_on_branch_re and skip_on_branch_re.match(branch):
             print "Release Candidate Build, leaving version files untouched."
             return 0