The Precipitation Processing System (PPS) has begun producing updated GPM radiometer products as of 12/4/2014 due to an error discovered in the calculation of the Sun Angle in the PPS Geolocation Toolkit. This is considered a minor update with the Product Version being incremented in letter only. Please see the list of affected products here: http://pps.gsfc.nasa.gov/Documents/GPM_PPS_SunAngle_Products_20141204.pdf
For most radiometers the sun angle is used as ancillary information, but for the TRMM microwave imager (TMI) the correction also slightly impacts brightness temperature and precipitation retrievals. Please see our preliminary analysis of the impact on retrievals document for details: http://pps.gsfc.nasa.gov/Documents/SunErrorMemo_20141204.pdf
There are no plans at this time to reprocess GPM data due to this issue. In addition, there are no plans to correct this error in the TRMM data stream at this time (ex: 1B11/2A12 TRMM products).