A big change will be coming to FT8 the on 10-Dec-2018 with the full release of WSJT-X 2.0.  This new software incorporates all of the updates added in the prior beta versions of the software. Some of these features are:

1. NA VHF Contest operation with support of grid locators and "/R" (Rover) call signs
2. EU VHF Contest operation with the exchange of 6-digit locators, QSO serial numbers, and "/P" (portable) call signs
3. ARRL Field Day operation with standard Field Day exchanges such as "6A SNJ"
4. ARRL RTTY Roundup operation with standard contest exchanges such as "579 NJ" or "559 0071"
5. Compound and nonstandard call signs (up tp 11 characters); no need for distinctions about "Type 1" or "Type 2" prefixes/suffixes
6. A special "telemetry" message format for exchange of arbitrary information up to 71 bits
7. All features of FT8 DXpedition mode, as in WSJT-X v1.9.1

Additionally this software incorporates a new 77 bit information payload.  This will make it incompatible with the current 75 bit payload used in version 1.8.X and 1.9X.  With the change in the protocols the reception of calls utilizing the 75 bit payload will eventually drop off as the new software becomes the standard for FT8.

For more information see https://physics.princeton.edu/pulsar/k1jt/wsjtx.html