Just a quick update.
All it does it changes the HTTPPipelining debug option to off again because it is causing texture corruption for some people. I finally managed to reproduce it on (who would have thought) human-heavy SIMs with human-heavy-content.
You don't necessarily need this update, you can just switch the option off yourself in 2.9.9 but this is so you get the latest version properly working if you're coming in new or updating from much older versions.
Should your stuff look like this, please either update or make sure to disable the option yourself, then clear your cache to make sure all corrupted textures are flushed.