AzureFlare is a drop in DLL mod for the official PSOBB client to allow for modifications without the need to edit PsoBB.exe, focused on compatibility with the official client rather than modifications such as the Teth executables.
At the time of writing this README:
Anything that is compatible with only Teth executables. For patches concerning them, there's Solybum's Blue Burst Patch Project (I just wanted to plug that project, it needs some recognition).
I looked for synonyms of Blue and Burst repectively and took 2 at random.
Head on to the Downloads page. You will need the latest C++ Redistributable to be able to use AzureFlare.