MrMC, the only forked version of Kodi that is in the official Fire TV appstore, has reduced the app’s price from $6.99 to $5.99, and it now also runs on Fire tablets. I’m told by the developers that the price was lowered to $5.99 because it was simpler to use a single binary for both tablets and the Fire TV, so the Fire TV price was lowered to match their usual tablet app prices, instead of raising the tablet price to match their usual TV app prices. For comparison, MrMC remains $6.99 on the Apple TV and $5.99 on iPhone/iPad because iOS devices use separate MrMC binaries for the two platforms. While the new price is certainly still too high for most Kodi users, since Kodi is available to sideload for free, having an official app is worth it for some.
As for the new tablet support, buying the app for the Fire TV will allow you to install it on supported Fire tablets, and vice versa. All Amazon made tablets that support Fire OS 5 are supported by MrMC. That includes the Fire HD 6 & 7 released in 2014, the newer Fire HD 8 & 10 released last year, and the $50 Fire tablet. Of course, the app also supports the Fire TV 1, 2, and Fire TV Stick.
Changes in version 2.3 of MrMC being released today focus primarily on bug fixes and the new tablet support. The app’s developers tell me they’re hoping to build in refresh rate switching into the app by the next version. That feature allows the app to automatically change the Fire TV’s video output refresh rate to match the content being watched, resulting in a perfect 1-to-1 match of your TV’s refresh rate to the frame rate of the video file. This is a feature many videophiles have been wanting out of the Fire TV ever since it first debuted. If MrMC’s developers can pull it off, it’ll be the first Fire TV app so have refresh rate switching, which is a feature even Amazon’s own video player can’t perform.