Update jQuery Flot from 0.6 to 0.8.3
Replace bxGallery and FancyBox with PhotosetGrid and ColorBox
Fix height of Administration Tool boxes
Fix $PHP_SELF so it works in subdirectories (the use basename() produced invalid links when viewing pages in the ext/ directory)
Let PHP handle the session garbage collection to have the same behaviour as file based sessions regarding session life time
Don't accept GET and POST session IDs if SESSION_FORCE_COOKIE_USE is true
Only set the session_id if it differs to the cookie value (session_id($id) always sends a cookie in session_start() and SID is always set, so we do this only when needed)
If SESSION_FORCE_COOKIE_USE is enabled and the first request is made to login.php, no cookie is found (but is set) so perform another check before redirecting directly to the cookie_usage.php page
Block orders where the shipping address does not match a defined shipping module zone
Bugfix: Double Query

Remove double query, thanks to Matt @mattjt83
Remove check on nonexisting $free_shipping variable
Add message stack output to checkout confirmation page
Force HTTPS on Admin when SSL is enabled
New Content Modules implementation for the Account, Checkout Success, and Login pages.
update version
Introduce new Card Acceptance box
Introduce Log In with PayPal content module
Update PayPal Express Checkout payment module
Update PayPal Payments Standard payment module
Update PayPal Payments Pro (Direct Payments) payment module
Update PayPal Express Checkout (Payflow Edition) payment module
Update PayPal Payments Pro (Payflow Edition) payment module
Introduce PayPal Payments Pro (Hosted Solution) payment module