Vertx: Difference between io.vertx.reactivex and io.vertx.rxjava

Each time, when I return to development with Vertx, I have to decide what package to use: io.vertx.rxjava or io.vertx.reactivex? This is a reason, why I created this post.

io.vertx.rxjava package uses RxJava 1. io.vertx.reactivex package uses current RX extension – RxJava 2.