To make things 100% clear, this isn't the official release. It's an early access release which is pretty damn near complete and has all the essential new features and tools. There are a few more things we plan to add in, mostly targeted at first-time users, but we're going to put those in over the next few weeks. In the meantime, you can start using the new dressing room and head creator, the new lighting, and all the other bits and pieces. There are no tutorials for the new stuff yet, but you can probably work it out!
You need to go through a couple of steps to get the early access version, but there's full instructions on the Web site. You can stick with your current version if you want, or you can run the two side by side. If you get 1.4 now, it should be easy to upgrade to the official release when it comes out.
We really want to hear your thoughts on this release, so please tell us what you think via the forums. Most of the team are on holiday next week, so we may not respond as fast as usual, but as always, we really value your feedback. It would be really useful to find out which bits you found confusing - that will help immensely when it comes to making the new tutorials.