New

Add support for deprecated blocks (61fdc50)
Add support for block "visibility:" option so that fixed blocks can "reuse" the delete button to switch the block visibility (a302738)
url conversion for @ font-face declarations (37fa7d5)
Better accessibility for boolean and select widgets ("replaced checkbox" and selectize) (bc2ec39)
Improve accessibility for new selectize elements (focusing and movement by keyboard) (f25eed9)

Fix (regressions since 0.18.x)

fix new variant code when applied to themed (style) properties (8cc8a97)
Fix automatic usage-tracking for src when using the new widget (a1d8a10)
Fix conditional bindings for css properties (-ko-prop-if and -ko-prop-ifnot) when used together with other css properties (1ed994d)
fix removal of data-ko-properties after processing when applied to data-ko-block elements. (60b7412)
Make sure to include the Url utility (c2d9710)
fix: new "buttonset" does not update selection when the value is updated outside from the widget (e.g: undo/redo) (e4cebd6)
fix error results for new development backend image manipulation functions. (704175a)
prevent small flickering introduced by the new debounce mode (4ae5ad9)