Microsoft announced on the Skype blog a new version of Skype for iOS will be available in mid-June. Preview screenshots show an app with a flatter look in keeping with the design aesthetics introduced by Apple in iOS 7.
To that end, this latest version, 5.0, will require iOS 7 or higher, and at least an iPhone 4. On the Skype for iPhone page, there are a few screenshots and a number of videos outlining the changes. In addition to the flatter design mentioned above, the update should be faster.
Screenshot of the new version of Skype.
There are also improvements to synchronization for those who run Skype in multiple places. If you receive a notification on your mobile device, it will be marked as read on your computer, and vice versa. And if you are offline while someone tries to send a message or a file, it's waiting for you you when you sign back in.
Overall it looks like a nice update for the iPhone version. The Skype blog also said the iPad version will be getting some attention in the near future.