Why WoTLK?

One of the most common questions beginner wow modders have is why so many projects in WoW are based on WoTLK specifically. After all, modern versions of the game offers tons of graphical and performance improvements, new cool gameplay mechanics like dragon riding and tons of more content to play with, so why are most of us still editing an almost 15 year old version of the game?

TLDR

There are virtually no tools or working emulators for other versions of the game, and creating/upgrading them would be a monumental task.

Full Answer

Versions of the game past WoTLK use very different file formats and server programming which is incompatible with virtually all the tools and servers we have developed for WoTLK over the years. Moving to a more modern version of the game would require us to more or less reinvent the wheel in almost every aspect.

Server cores beyond Cataclysm are either functionally sandboxes or leaks from closed projects that open source developers have no interest in maintaining. This is both for ethical reasons and because leaks often have very poor programming (“hackfixes”) that make them hard to base any serious development on, especially custom content.

Modding tools for versions other than WoTLK are very few and far between, and many of the games file formats have become significantly more complex over the years.

Is WoTLK the ONLY option?

Projects like Epsilon and Prophecy RP are based off modern versions of the game, but have to develop and maintain their own tools and don’t have or plan to have a lot of ‘normal’ gameplay since the emulators barely support it.

Cataclysm is one of the very few modern versions of the game with a decent and maintained emulator, and even supports a few of the modding tools we have. However, it is still significantly more difficult to create extensive mods for to a complete novice.