Link to the changelog: http://api.pagelines.com/changelog
Points of Interest:
* pl_dynamic_css_url filter added for sites with mixed SSL
* pl_force_ssl action added to force SSL in css.
* New navbar title option on small screens.
* Using wp_title() filters now for SEO plugins.
* New file based css cache.
So obviously the most important thing here is the new file based cache. When the CSS is saved and this mode is active a css file will be written to a pagelines dir in your uploads folder. If for any reason the folder is not writable the CSS system will fall back and use the dynamic url method which relies on browsers caching the file.
So to enable this you need to add something to wp-config.php, the reason for this is its experimental and an advanced feature, thats why at the moment it isnt a framework option. Its up to you
Add the following to wp-config.php right below the WP_DEBUG line:
define( 'LESS_FILE_MODE', true );
Now every time you save the PageLines settings a new file will be written out.
The upgrade will go live on the servers in a few hours @slingr