I tried applying this patch, and in some cases it works, but I noticed I was getting errors like
So, I upgraded the POM to the latest version of the plugin
And now the patch has compilation errors in over a dozen places. This is a big challenge with the configuration slicing plugin - it is very hard to keep up with changes to the plugins it slices. If the authors of the email-ext plugin want to maintain the slicer, that would be awesome. But I cannot commit the patch as-is.