No, there will be changes to the  file-naming convention, see Dissemination file-naming changes from IFS Cycle 49r1 to 50r1

Yes, due to the nature of the upgrade, ECMWF will transfer all installed requirements in the test PREd to the production system on the day of the cycle implementation. During the RCP, any changes made in the production system should also be installed in the test system to ensure continuity.  

The same TOTP token should be used for the xdiss as for the diss system.

This varies from day-to-day and depends on the data set as well. Some days the delay is a couple of hours, while some days there might be a day or two lag. Usually as we get close to implementation the delay gets smaller.

 AIFS has a separate update cycle from the IFS, but they are synchronised this time. Head over to Implementation of AIFS Single v2 and Implementation of AIFS ENS v2 for more info.

We would encourage this, yes. In the IFS Cycle 49r1, (ex) HRES and Ensemble Control are numerically identical. If the users make this change at IFS Cycle 49r1, then they won't need to make it at IFS Cycle 50r1.

In IFS Cycle 50r1 it will still be a blend of GRIB1 and GRIB2. Full migration to all GRIB2 will happen with IFS Cycle 50r2, planned for implementation in late 2026, with plenty of test data available during the year or so leading up to this. Read more in this article from Spring 2023 Newsletter and In Focus article:  Migration to GRIB2 data format: implications for users.

We are not planning to replace GRIB2 in the near future.

No, we will not be forcing users to migrate to the CCSDS compression with the IFS Cycle 50r1 update. However, we strongly recommend testing and switching to the CCSDS compression.