Please have a look at the wiki!
Current version: LLVM-4.0
You can cite Obfuscator-LLVM using the following Bibtex entry:
@INPROCEEDINGS{ieeespro2015-JunodRWM, author={Pascal Junod and Julien Rinaldini and Johan Wehrli and Julie Michielin}, booktitle={Proceedings of the{IEEE/ACM} 1st International Workshop on Software Protection,{SPRO'15}, Firenze, Italy, May 19th, 2015}, editor ={Brecht Wyseur}, publisher ={IEEE}, title={Obfuscator-{LLVM} -- Software Protection for the Masses}, year={2015}, pages={3--9}, doi={10.1109/SPRO.2015.10}, }