This userscript is now deprecated, as Twitch themselves have implemented recent chat history. BTTV also returns an empty array now. You should uninstall this userscript now.
As it may or may not still be in testing, if their native chat history does not work for you, try the following command in the dev tools console while on twitch, then refresh the page to test if it worked: window.Twitch.experiments.overrideExperimentValue('MESSAGE_HISTORY', 'on');
Does exactly what it sounds like.
Any userscript managerClick the raw button next to the script below.???Profit!
Initial working.
Fix multi-room weirdness.Add checks for BTTV being installed.