WSJT-X 2.0 Full Release now Available

The new protocols become the worldwide standards starting on December 10, 2018, and all users should upgrade to WSJT-X 2.0 by 1st January 2019. After that date, only the new FT8 and MSK144 should be used on the air.
— Joe Taylor, K1JT

The WSJT-X 2.0 software suite has been released, and developer Joe Taylor, K1JT, is urging FT8 and MSK144 users to upgrade to what will become the new standard

The FT8 and MSK144 protocols have been enhanced in a way that is not backwards compatible with older versions of the program. That includes any version 1.9 releases.

Quick Start Guide for WSJT -

FT8 Operating Guide by ZL2IFB -