diff --git a/docs/changelog/7.x.x.txt b/docs/changelog/7.x.x.txt
index b6d56323b..fade18db6 100644
--- a/docs/changelog/7.x.x.txt
+++ b/docs/changelog/7.x.x.txt
@@ -11,6 +11,7 @@
  - fixed: Asset Manager buttons now work in IE6
  - fixed: Donation: Add to Cart still visible in Thank You Message screen
  - optimized PurgeOldInboxMessages workflow
+ - fixed: Calendar: Reorder Events in Week View Broken
 
 7.5.15
  - fixed: Colorpicker window would not open (Martin Kamerbeek / Oqapi)
diff --git a/docs/upgrades/upgrade_7.4.40-7.5.16.pl b/docs/upgrades/upgrade_7.4.40-7.5.16.pl
index ba3e2ce00..c2cdcd377 100644
--- a/docs/upgrades/upgrade_7.4.40-7.5.16.pl
+++ b/docs/upgrades/upgrade_7.4.40-7.5.16.pl
@@ -124,8 +124,19 @@ unlockShelfAssets($session);
 removeOldGalleryImport($session);
 addMissingWorkflowActivities($session);
 addIndexToInbox($session);
+fixEventSequenceNumbers($session);
 finish($session); # this line required
 
+#----------------------------------------------------------------------------
+sub fixEventSequenceNumbers {
+    my $session = shift;
+    print "\tFixing Event sequence numbers... " unless $quiet;
+    $session->db->write('set @seqNum=0');
+    $session->db->write('select MAX(sequenceNumber) into @seqNum from Event');
+    $session->db->write('update Event set sequenceNumber=@seqNum:=@seqNum+16384 where sequenceNumber IS NULL order by revisionDate');
+    print "Done.\n" unless $quiet;
+}
+
 #-----------------------------------------------------------
 sub addIndexToInbox {
     my $session = shift;
diff --git a/docs/upgrades/upgrade_7.5.15-7.5.16.pl b/docs/upgrades/upgrade_7.5.15-7.5.16.pl
index f94cc332d..4014daed7 100644
--- a/docs/upgrades/upgrade_7.5.15-7.5.16.pl
+++ b/docs/upgrades/upgrade_7.5.15-7.5.16.pl
@@ -29,6 +29,7 @@ my $quiet; # this line required
 my $session = start(); # this line required
 
 addIndexToInbox($session);
+fixEventSequenceNumbers($session);
 
 finish($session); # this line required
 
@@ -40,6 +41,16 @@ sub addIndexToInbox {
     print "Done.\n" unless $quiet;
 }
 
+#----------------------------------------------------------------------------
+sub fixEventSequenceNumbers {
+    my $session = shift;
+    print "\tFixing Event sequence numbers... " unless $quiet;
+    $session->db->write('set @seqNum=0');
+    $session->db->write('select MAX(sequenceNumber) into @seqNum from Event');
+    $session->db->write('update Event set sequenceNumber=@seqNum:=@seqNum+16384 where sequenceNumber IS NULL order by revisionDate');
+    print "Done.\n" unless $quiet;
+}
+
 
 #----------------------------------------------------------------------------
 # Describe what our function does