Varnish 3 to 4 upgrade config changes

Basically, yes, you rename all your functions, and alter all of your calls to work with the new language syntax.

It might be easier to just write the vcl file from scratch, using what you know from the v3 version. However, it should be quite possible to just convert the VCL to v4, by going over your code, using the migration guide here: http://varnish-cache.org/docs/5.0/whats-new/upgrading-4.1.html Edit: I've since found this tool, which helps https://github.com/fgsch/varnish3to4 It's not a magic bullet, you will still need to convert, but it should help.

EditEdit: Added @Jay Huggins's updated link