I the new upgrade versions v1.50 RSD for free for existing licence users here or with an high discount price?

Please read your email that you have received from coffecup about the beta version.

Here what it said

Make 2016 a responsive year

With the rise of mobile devices, responsive design has become a requirement. The unique Responsive Site Designer makes developing a flexible website a breeze. Grab it today and get a instant $60 savings. Discount valid until the public release of V1.5 — which will be a free upgrade of all existing owners, so don’t miss out!

Very Merry Christmas