14.6.6 is an optimization release comprising quite a few improvements and bug fixes. You will find improvements to many of our acceleration features.
We have removed on-the-fly Image Compression. That means an image that is not cacheable will not be processed at all. Until now, we would perform a compression experiment without storing the result. However, we have decided to trade TTFB for download size. Furthermore, we have better handling for color profiles in WebP images and the Image Compression cache needs less space than ever.
Our HTML5 parser now fully adheres to the W3C Recommendation to detect the encoding. Most of the time, the character set is determined from a byte-order-mark or the
Content-type header field. If neither of those are present, our new scanner reads the encoding from the
<meta> tags in the document itself.
As usual, the update ships fresh 3rd-party libraries to carry on upstream security and stability fixes.
The changelog provides a thorough list.