Notice for those receiving Himawari 8 directly or via relay from GOES 16 or 17. The scheduled transition from Himawari 8 to Himawari 9 (which is patiently waiting for on-orbit since 11 November 2016) has been rescheduled from April 2022 to December of 2022, at which time Himawari 9 will become primary and 8 will be placed into on-orbit storage.
JMA could not tell me as of yet if the LRIT headers would remain the same for Himawari 9 as Himawari 8 but it seems likely that they will change them.
I have raised an issue on the goestools github page with more information for that particular software. For both GOES 18 and Himawari 9
https://github.com/pietern/goestools/issues/122
Carl