Skype for Linux is not updated nearly as often as it is on the Mac or on Windows. Smaller userbase and slightly more complex multimedia arrangements on linux make updating the client slightly more difficult. That being said, they've made a whole mess of improvements.

Skype Journal has a full list of changes. The most interesting change is the various enhancements they made in the UI with drag and drop. This makes it much easier to use.

The other interesting piece of news, acknowledged on Skype's Linux blog was that they are planning on adding video support in the next release. I'll believe it when I see it.