may be the prefix should be add to some css value too?

[superwf]

In my case, the css is below
background-image: radial-gradient(farthest-corner, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.95));

It is ok in most browser except safari(window7-64 version), then I add the css below only for safari
background-image: -webkit-radial-gradient(farthest-corner, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.95));

May be myth should add browser prefix to css value part, I think.
Thank you.

[MoOx]

Latest version of autoprefixer (5.x) seems to handle this but myth still use 3.x.

[ianstormtaylor]

Fixed in 1.5.0!