GFS Model Upgrade 15.2.0 is expected on November 7, 2017 at 12Z. This is a minor upgrade. Mainly with the ingestion of new satellite, SST data and some bug fixes.
We do not expect any interruptions in model output.
Here is a full description of the changes from NOAA.
https://www.weather.gov/media/notification/scn19-84gfs15_2.pdf