My preferred DDS
library tool is PVRTexTool, which lets me convert it to KTX format.
KTX has the advantage that it's unambiguously documented (though, you probably couldn't care less since there's a ready-to-use loader library!) and that it loads into something you can directly feed to OpenGL. All the constants and such are already correct as OpenGL expects them, no need to do any obscure translations from some DirectX constants (which sometimes change meaning with a different version) to some other OpenGL constants. Just give OpenGL what's in the file. To me, that is a big, big plus.