6 Wunderkinder, the developers behind the ‘Wunderlist’ to-do app that’s currently home to over 4 million users, today announced a new “Pro” version of the cross platform productivity app. Launching today on iPhone, iPad, Mac, and on the web, the new pro version comes with the introduction of the developer’s first premium model that will see users pay $4.99 a month (or $49.99 a year) to get access to new team oriented collaboration features:

Assigning – now you can add an extra level of accountability and assign tasks to your colleagues

and friends.
Unlimited subtasks – sometimes the task on hand is so big that you need to break it down into

small manageable subtasks. Now you can add as little or as many needed to get the job done.
Backgrounds – Wunderlist Pro subscribers will have access to eight new backgrounds – from a minimal dark wood and soothing sands to vibrant florals and the Paris cityscape, plus a whole lot more!

6 Wunderkinder plans to keep adding additional features for pro users, including the ability to attach and share files through tasks:

Files will be the next feature to be added to Wunderlist Pro. With the support of Files you will be able to attach files to a task and share with your colleagues, for improved collaboration outside of just the to-dos.

The Pro upgrade for Wunderlist is available now as an in-app purchase in the Wunderlist iPhone & iPad app as well as the Mac App Store app and on the web.

Those that plan on sticking with the free version of Wunderlist will also be greeted today with new features in update 2.1.0 of the app. Among them is a new Action Bar and other UI improvements such as the ability to “Get a quick overview as to who created and completed a task with the Detail View.”