This is a head task to collect the release-blocking regressions.
=== Patches ===
Patches to restore Krita's own Wintab support are in the `abrahams-testing` branch. Qt's builtin Wintab support must be disabled for the patch to work. Patch is here. https://phabricator.kde.org/F33182
XCB patches are also merged in the `abrahams-testing` branch. These do not require any changes to Qt, but the patches are not yet complete.