Krita 3.1 beta available.

The Krita 3.1 beta come with a full features and fixes.
The most useful features can you be found into this 2D software for drawing:

• ffmpeg-based export to animated gif and video formats;
• the OpenGL canvas is fixed;
• will officially support OSX
• fixing bugs on Windows and Linux
• the beta still contains the colorize mask/lazy brush plugin
• expecting to experimenting with new algorithms, but with the next release 
• same splash screen like old version

You can read more abiut this here. 
Krita come with this free copyright for Krita

Krita is free software under the GNU Public License, Version 2 or any later version at your option. This means you can get the source code for Krita from . The license only applies to the Krita source code, not to your work! You can use Krita to create artworks for commerical purposes without any limitation.

Krita Shell Extension come with MIT copyright. Krita Shell Extension
The MIT License
Copyright (c) 2016 Alvin Wong