Added a better mechanism for calculating when content was last modified for cache headers.

docs/changelog/7.x.x.txt

@@ -1,6 +1,8 @@
 7.6.3
  - fixed #8989: Missing profile field "showOnline" for the UsersOnline macro.
  - Added DataTable to WebGUI.conf.original
+ - Added a better mechanism for calculating when content was last modified for
+   cache headers.
  - The Syndicated Content asset was rewritten, and now uses 35% less memory
    and is 400% faster.
  - fixed #9025: Testing function of UsersOnline macro fails.

docs/gotcha.txt

@@ -16,6 +16,8 @@ save you many hours of grief.
 	there will be problems that the migration cannot handle. Check your
 	Syndicated Content assets after upgrade to ensure they are still
 	working as expected.
+	
+  * You must upgrade to 7.6.2 before you can upgrade to 7.6.3.
 
 
 7.6.1

docs/upgrades/upgrade_7.6.2-7.6.3.pl

@@ -29,12 +29,21 @@ my $quiet; # this line required
 
 my $session = start(); # this line required
 # upgrade functions go here
-
+createLastUpdatedField($session);
 createFieldShowOnline($session);
 upgradeSyndicatedContentTemplates($session);
 
 finish($session); # this line required
 
+#----------------------------------------------------------------------------
+sub createLastUpdatedField {
+    my $session = shift;
+    print "\tAdding last updated field to all assets... " unless $quiet;
+    my $db = $session->db;
+    $db->write("alter table assetData add column lastModified bigint");
+    $db->write("update assetData set lastModified=revisionDate");
+    print "DONE!\n" unless $quiet;
+}
 
 #----------------------------------------------------------------------------
 sub upgradeSyndicatedContentTemplates {