MyPaint full changelog

HSV/HCY brush dynamics in 2.x mode fixed.
Undo/Redo stack size made configurable and more efficient.
Undo/Redo stack default size increased to 40.
Rounding error when saving files in 2.x mode fixed.
Invalid l11n strings fixed.
Translated strings added/updated for several languages.
Dependency on intltool removed (still required for libmypaint).
Variables in l11n strings validated on build (xml tags are not validated yet, however).
libmypaint translations are now bound, making them work properly in the appimages.
OARS rating added to appdata (relevant for app-distribution software, but not much else).
A number of Py3 compatibility issues were fixed.
Svg icons fixed - some were previously considered invalid by librsvg >= 2.48.
Svg icon sizes reduced across the board.
Windows build now uses openmp, which should improve performance on most systems.
Size of Windows install bundle significantly reduced. (installed size by ~50%, bundle size by ~70% for installers)

Full Python3 support (Python2 still supported)
Tons of style consistency updates (flake8).
Switch to PyGI
New ability to simplify nodes in Inking tool.
New ability to delete autosaves from recovery dialog.
Improved user messages.
Scratchpad no longer scrolls on size changes
Integrated bug reporting w. issue template
Use external libmypaint (>= 1.5).
Most (possibly all) IO uses context managers.
Layer manipulability dependent on visibility.
Brush description shown in tooltip in quick choice dialog.
AppImage builds added.
Move build to setuptools/distutils.
New keyboard shortcuts/defaults.
New symmetry modes (vertical, vert+horz, rotational, snowflake).
Flatpak support added (currently not functional?).
Maximum input mapping curve points increased to 64.
Curve editor points snaps on 0.5 increments.
Input curve reset button clears the graph.
New Import Layers feature.
Zoom and view-rotation-dependent painting.
New debug command: Vacuum Empty Tiles.
Progress feedback for loading/saving.

BINARIES:
Windows users can run the installers below. Please uninstall all old versions of MyPaint before you do this, especially if you're about to install over an existing location. You shouldn't lose your settings or scraps if your old install is normal. Use “Add or Remove Programs” to do the removal(s), and make backups of your important files if you're worried.
Alternatively, please try the standalone zipfile bundles. These need to be unpacked somewhere before they can be used, for example onto a portable USB drive, and the integration with Windows is more limited.
Users of Ubuntu or its derivatives can add the MyPaint-Testing PPA as a software repository, and they'll then receive automatic updates.
For other operating systems, please contact your friendly maintainers and ask them to make fresh builds from these sources.
BUGS:
(Windows only) this build contains GTK 3.22.7, a large increment which fixes a lot of graphics tablet bugs and crashes.