Pencil2D is an easy, intuitive tool to make 2D hand-drawn animations. Pencil2D is open source and cross-platform.
What's new in 0.6.4: https://www.pencil2d.org/2019/05/pencil2d-0.6.4-release.html
What's new in 0.6.3: https://www.pencil2d.org/2019/03/pencil2d-0.6.3-release.html
What's new in 0.6.2: https://www.pencil2d.org/2018/09/maintenance-release-0.6.2.html
What's new in v0.6.1: https://www.pencil2d.org/2018/04/maintenance-release-0.6.1.html
What's new in v0.6 https://www.pencil2d.org/2017/12/introducing-pencil2d-0.6.html