What is perhaps one of the most popular Android keyboards, and one of the top apps for Google's mobile operating system, is now free.

Swiftkey Keyboard today announced that it is doing away with the $3.99 price for its app. In a press release, the company noted that the shift comes alongside an update to the app that introduces dozens of new free and premium keyboard themes. 

SwiftKey Keyboard learns a user's typing style and word choice over time, aiming to improve typing with more accurate autocorrect, prediction of the next word and other innovations like SwiftKey Flow, which lets users type by sliding a finger across the screen. 

Key to the free model will by Swiftkey's ability to push its premium keyboard themes as in-app purchases. Existing SwiftKey users who have previously paid for the app can download a $4.99 “Premier Pack” of 10 themes free of charge. The app’s core functionality remains intact.

On top of premium offerings, SwiftKey also added some improvements to the app, including support for over 800 emoji, with a new prediction feature that learns how emoji are used and predicts them as the user types. An optional dedicated number row is now available for the keyboard, making it easier to input numbers, and SwiftKey’s word prediction engine now offers better autocorrect and more accurate gesture typing, and new global languages have been added, bringing the total number supported to 66.

SwiftKey's move to making its app free is part of a broader trend among developers. Gartner now predicts that nearly 95 percent of all apps will be free by 2017, with developers opting for a "freemium" model, where users can purchase add-ons and extras from within the app.