This past week we updated both MaxButtons and MaxButtons Pro after being informed there was a possible vulnerability (there were no confirmed breaches, simply a test), so we acted as quickly as we could to make sure we patched up the holes. You won’t see much of a difference on you end unless you are looking at the “View CSS” page from the button editor.
The new View CSS uses a tiny JS script and some CSS to show the CSS inside a modal that will pop up above the content in standard lightbox fashion. If you experience any issues with this please let us know. In saving you the hassle of opening an extra browser window, we’ve also taken out the need for wp-load.php which some people had expressed was giving them issues. That problem should also be alleviated.
To get 1.21 or 2.3.5, upgrade from the WordPress dashboard or download the new version and upload via FTP. Be sure to de-activate and re-activate if things aren’t working quite right. If you experience any issues, head to the forums and let us know!