What's the difference between BERT and RankBrain?

Hi Friends,
BERT does not replace RankBrain, it is an additional method for understanding content and queries. It's additive to Google's ranking system. RankBrain can and will still be used for some queries. But when Google thinks a query can be better understood with the help of BERT, Google will use that.

BERT is not a replacement for RankBrain, but rather a supplement to the technology. Both algorithm updates share the similar goal of improving user experience and the relevancy of search results