So... try 3!

+ Fixed startup error for 1.8.8.
+ Fixed those weird slashes coming up in challenges (was previously a regex fix that is no longer needed, as we can see)
+ Added a pickup head feature where you can middle click a block and it'll not only pick up the head like normal, but set the name and texture. Once again thank you to the amazing jascotty2 for doing this!
+ Added /addhead <Player>, of which lets you add a player's head to the head selector. In the config, you can even have it so that it adds those heads automatically (in the "autograb" section). Thanks to jascotty2 for doing this too!
+ Fixed "Page -1" in /heads and /hpc.
+ Probably a /heads fix.

And if you updated to v6.3.5, these fixes urgently took place for your convenience:

+ Prices glitch for /heads
+ Removed stacktraces printed when using /hplb
+ Added more checks to /addhead to make sure that usernames are the correct length