lighttpd improved is lighttpd 1.4 branch with severals useful modules. We don't choose lighttpd 1.5 because lighttpd 1.5 is little away from daily use of productive environment. Currently mod_cache, mod_mem_compress and mod_mem_cache are included. These modules are written for faster web service, for better user experience.

mod_cache is squid-like cache module. mod_mem_cache is to cache local files into memory. mod_mem_compress is to store compress local files into memory