Our 3 auditors were funded by the community to ensure that the implementation did not contain any critical bugs or exploits.The final reports were released during the summer of 2018, with several useful corrections and fixes suggested, and the final bulletproof implementation has been added first to Monero Stagenet, and then to the main Monero network during the October 2018 network upgrade.
More explanations on Monero's implementation of bulletproofs could be found on youtube fondajo channel in a [conversation with Sarang Noether](https://www.youtube.com/watch?v=6lEWqIMLzUU).