https://www.subseatechnologies.com/hemisphere-gnss/technical-bulletins/
Hemisphere GNSS Technical Bulletins
04/01/2020 - COVID-19 Update (external link)
02/01/2019 - April 26, 2019 "GPS Week Rollover"
03/07/2018 - Atlas GNSS Global Correction Service Technical Bulletin
12/12/2016 - December 2016 "Leap Second"