On August 2nd, R80.20.50 Build 992002773 was released.
About a month earlier, R81.10.00 firmware was released and stated:
R80.20.xx code base for 1500/1600/1800 Series Security Gateways will continue to be supported, in the near future – with further releases, and in the medium term – with stability, performance, and bug fixes only. As the majority of R&D efforts will now shift to R81.10 code base, we encourage our customers to start evaluating and migrating to the new code base.
CCSP - CCSE / CCTE / CTPS / CCME / CCSM Elite / SMB Specialist