This page lists the incompatible changes to the style scheme file format.
The <author> tags are no longer supported, so you should
remove them.
The support for the parent-scheme attribute has been removed. It
was unused. If you relied on it, copy and adapt the content of the parent
scheme.
The support for the line-background attribute (for the
<style> tag) has been removed.
You need to add the kind attribute (for light/dark), a new
mandatory attribute.
The version attribute of the <style-scheme>
element is no longer supported, so you should remove it.
The parser is now a bit more strict, check if there are warning messages printed in the terminal if a style scheme fails to load.