diff --git a/docs/changelog/7.x.x.txt b/docs/changelog/7.x.x.txt
index 5fd31e858..4128f539a 100644
--- a/docs/changelog/7.x.x.txt
+++ b/docs/changelog/7.x.x.txt
@@ -22,6 +22,7 @@
  - fixed: international characters corrupted in titles
  - fixed: Users without karma can transfer karma by rating posts
  - fixed: gateway macro not usable in links in rich editor
+ - fixed: iCal feeds don't update properly when events are changed
 
 7.5.9
  - fixed: Collaboration System attachments follow site's max size instead of CS's
diff --git a/docs/upgrades/upgrade_7.5.9-7.5.10.pl b/docs/upgrades/upgrade_7.5.9-7.5.10.pl
index 0195491a7..faf1a4ade 100644
--- a/docs/upgrades/upgrade_7.5.9-7.5.10.pl
+++ b/docs/upgrades/upgrade_7.5.9-7.5.10.pl
@@ -24,6 +24,7 @@ my $session = start(); # this line required
 
 privatizeVisitor($session);
 ucfirstThingyFieldTypes($session);
+addEventSequenceNumber($session);
 
 finish($session); # this line required
 
@@ -36,6 +37,15 @@ finish($session); # this line required
 #    print "DONE!\n" unless $quiet;
 #}
 
+#----------------------------------------------------------------------------
+sub addEventSequenceNumber {
+    my $session = shift;
+    print "\tAdding iCal sequence number to events... " unless $quiet;
+    $session->db->write('ALTER TABLE Event ADD COLUMN iCalSequenceNumber int');
+    $session->db->write('UPDATE Event SET iCalSequenceNumber=0');
+    print "Done.\n" unless $quiet;
+}
+
 #----------------------------------------------------------------------------
 sub privatizeVisitor {
     my $session = shift;
diff --git a/lib/WebGUI/Asset/Event.pm b/lib/WebGUI/Asset/Event.pm
index 536aba63e..91e8704dc 100644
--- a/lib/WebGUI/Asset/Event.pm
+++ b/lib/WebGUI/Asset/Event.pm
@@ -43,6 +43,21 @@ use WebGUI::DateTime;
 
 =cut
 
+sub addRevision {
+    my $self = shift;
+    my $newRev = $self->SUPER::addRevision(@_);
+    my $sequenceNumber = $newRev->get('iCalSequenceNumber');
+    if (defined $sequenceNumber) {
+        $sequenceNumber++;
+    }
+    else {
+        $sequenceNumber = 0;
+    }
+    $newRev->update({iCalSequenceNumber => $sequenceNumber});
+    return $newRev;
+}
+
+
 ####################################################################
 
 sub definition {
@@ -114,6 +129,9 @@ sub definition {
         sequenceNumber => {
             fieldType       => 'hidden',
         },
+        iCalSequenceNumber => {
+            fieldType       => 'hidden',
+        },
     );
     
     
diff --git a/lib/WebGUI/Asset/Wobject/Calendar.pm b/lib/WebGUI/Asset/Wobject/Calendar.pm
index ce522f132..74e4f7d37 100644
--- a/lib/WebGUI/Asset/Wobject/Calendar.pm
+++ b/lib/WebGUI/Asset/Wobject/Calendar.pm
@@ -1868,11 +1868,29 @@ sub www_ical {
                 . WebGUI::DateTime->new($self->session, $event->get("creationDate"))->toIcal
                 . "\r\n";
         
+        # SEQUENCE
+        my $sequenceNumber = $event->get("iCalSequenceNumber");
+        if (defined $sequenceNumber) {
+            $ical   .= qq{SEQUENCE:}
+                    . $event->get("iCalSequenceNumber")
+                    . "\r\n";
+        }
+        
         # DTSTART
-        $ical   .= qq{DTSTART:}.$event->getIcalStart."\r\n";
+        my $eventStart = $event->getIcalStart;
+        $ical .= 'DTSTART';
+        if ($eventStart !~ /T/) {
+            $ical .= ';VALUE=DATE';
+        }
+        $ical .= ":$eventStart\r\n";
         
         # DTEND
-        $ical   .= qq{DTEND:}.$event->getIcalEnd."\r\n";
+        my $eventEnd = $event->getIcalEnd;
+        $ical .= 'DTEND';
+        if ($eventEnd !~ /T/) {
+            $ical .= ';VALUE=DATE';
+        }
+        $ical .= ":$eventEnd\r\n";
         
         # Summary (the title)
         # Wrapped at 75 columns