Dear NWP centers: We would like to inform you that a major software update to Sentinel-6 A (aka S6MF) is being planned to occur no earlier than January 27, 2025 to enable the tracking of Galileo radio occultation. During the upload period (which is expected to last several days) there could be instrument outages impacting the number of BUFR products distributed on the GTS. We expect little or no impact on GPS and GLONASS RO from this update. Therefore, we plan to begin releasing these data operationally to the GTS after a 7-10 day checkout period following the upload has completed. Another announcement will follow when the GPS and GLONASS BUFR products are being distributed operationally on GTS. The Galileo RO data will be processed and be made available offline separately for a more extensive evaluation by NWP centers before their operational release. If you have any question, please do not hesitate to contact us. Sincerely, Chi Ao, on behalf of the S6 RO Team from JPL and EUMETSAT