Varnish Cache 4.0 技术预览版 1 在13年12月5日就发布了，改进内容包括：
Full streaming support, including asynchronous backend fetches. This enables Varnish to serve stale objects while it is fetching or revalidating objects from the backend.
If-Modified-Since and If-None-Match support to the backend.
Directors are now VMODs and are runtime loadable.
A complete overhaul of the libvarnishapi and corresponding tools,leading to performance and correctness improvements.
A fully-fledged filtering language for querying the Varnish logs.
请注意 VCL 语法已经更改。
下载地址：http://repo.varnish-cache.org/source/varnish-4.0.0-tp1.tar.gz
来自:开源中国社区
