Am I correct that Krita is more of a tool for sketch artists? Just curious. When I've looked at their website briefly, I got that impression from the graphics on the website.
A quote from the page you linked: "THE FILE FORMAT FOR VECTOR LAYERS HAS CHANGED."
Many questions:
"file format"? Layers have a separate file format? Or do they mean the code, or the system which Krita uses for layers?
"vector layers"? Exactly what is a "vector layer"? Is that referring to an SVG standard for layers?
If there's a new SVG standard for layers -- then let's have it, Inkscape! But I suspect there's some....either unspecific language in that comment, or someone making something a little too non-technical. Could they mean that Krita 4 is going to use special groups to facilitate layer-like functionality, like Inkscape does?
