Viber is set to be updated today to version 4.1, thereby gaining more stickers and, more importantly, launching a significant new feature.

A month ago, the popular messaging app received its 4.0 update, which saw the debut of the Sticker Market along with the arrival of other improvements including push-to-talk.

This month, which happens to be its third anniversary month, Viber is being updated with even more stickers to download in the Sticker Market.

If you can’t see the video embedded above, please click here.

But the highlight of Viber 4.1 is the official launch of Viber Out, a new feature similar to Skype Out that allows users to make calls to any mobile or landline number in supported countries.

Viber Out was soft-launched in the Philippines last month as part of Viber’s efforts to help users contact their family and friends in the aftermath of Typhoon Haiyan‘s devastation in the country. Now, though, the service is being launched worldwide with the release of Viber 4.1.

Viber Out requires Viber credits, which are available via in-app purchase in $0.99, $4.99, and $9.99 denominations. According to Viber, because of its lower per-minute rates and omission of connection fees, Viber Out is considerably more affordable on a per-call basis than Skype Out. Check out the table below for a price comparison between the two services:

Viber Out vs. Skype Out

Viber 4.1 is set to be available later today in the App Store for free. It’s optimized for iPhone and iPod touch running iOS 5.0 or later.