After more than a year of development Drupal 4.7.0 was released last Monday. This is a major release and will mean a major upgrade for many sites.

Yet from what I have counted "only" 198 of the 291 modules availalbe for 4.6 have been ported to 4.7 – so you should double-check before you upgrade.

This release has a lot of usability enhancements

• AJAX Auto-complete Fields(AJAX)
• Javascript reducing Clutter on Forms(JS): Added support for collapsible page sections within forms. This allows for more streamlined interfaces.
• AJAX supported uploading of files
• Install and Upgrade Module – Support easier
• Spam killers: better Organized Node & Comment Edit Forms and Mass Comment Operations

and so many more cool new features like

• Free Tagging Support AJAX based
• Public/Private Profile Fields: You can now specify permissions for profiles on a per-field basis.
• Aggregator now Supports Atom and RSS Feeds itself – also you can now configure how much content and how many items to publish in your RSS feed.
• Better Search Index: The search module indexer is now smarter and more robust and has a custom Search Results Ranking

Technical oriented features are

• New XML-RPC Library: The old XML-RPC library has been ditched and replaced for obvious reasons.
• Loose Caching Option: It is now possible to enable 'loose caching' which will improve Drupal's performance on sites with lots of posting activity.
• Better Performance for Path Aliasing: Path aliasing performance has been improved significantly, especially when using a large number of aliases.
• Page Creation Time: You can now easily track the page generation time for your site.
• Improved Unicode string handling API: better support for internationalization at the core.
• Support for Multibyte Strings: Drupal now supports for PHP's multibyte string extension for full Unicode support… let's go for some chinese drupal sites :-)
• Support for MySQLi: Drupal now supports PHP5's 'mysqli' extension.

Major change and tradeoff for this release is the incompatible new Forms API : the forms API has been refactored to make it possible to alter, extend or theme any form in Drupal…. but this means all modules using the old forms api (including one custom module I wrote) need to be portet

Update 06/23: – there's a list of tested modules and the status if they word for 4.7 without specific adaptions at RobbT's Site