The Wixie legacy UI will disappear this summer. For many users this means nothing. They have never seen the legacy UI and they don’t have a hyperlink that lets them switch into it if they want. For some, this just means that a hyperlink that they have never clicked in the upper-right corner next to Settings will no longer be there. For a few, it means they will start using the new UI instead of the one they were trained on over two years ago.
The old UI and new UI are very similar. The old one just did less. This summer it is going away. If you are one of the few people still using the legacy UI, you will have a lot of new features to look forward to when you return from summer break. If you want to check them out, click the “Use new interface” link and enjoy.