From Dr. George Huffman:

Summary: Processing issues were discovered with both series of data and 
it was decided to re-do the retrospective processings to correct the 
issues.  In general the original Version 7 data sets are considered an 
improvement over Version 6, but this additional processing is considered 
important to meet the goals of the project.

Details: It was recently discovered that AMSU data were neglected in the 
first retrospective processing of both the Version 7 TMPA (3B42/43) and 
TMPA-RT (3B40/41/42RT) data series, which creates an important 
shortcoming in the inventory of microwave precipitation estimates used 
during 2000-2010.  In addition, a coding error in the TMPA-RT replaced 
the occasional missings in product 3B42RT with zeros.  Accordingly, both 
product series are being retrospectively processed again.  The main 
impact in both series should be to improve the fine-scale patterns of 
precipitation during 2000-2010 (and for 3B4xRT into late 2012). 
Averages over progressively larger time/space scales should be 
progressively less affected.  [This is the reason the lack of AMSU went 
undiscovered; the merger system copes very reasonably with missing 
data.]  Nonetheless, users are urged to switch to the newest Version 7 
data sets as soon as they are computed and posted (in the next few 
weeks).  The newest runs may be identified by the file names:
V.7 3B42/43 suffix of "7A.HDF"   for January 2000 - September 2010
V.7 3B4xRT  suffix of "7R2.bin"  for 1 March 2000 - 6 November 2012

It continues to be the case that the Version 7 3B42/43 is some 5-8% 
higher than the calibrating data set (2B31) over oceans, which is 
believed to be erroneous.  However, the first several attempts at 
diagnosing this issue have not been fruitful.  At the large scales this 
offset seems to be nearly a proportional constant.

We apologize for the thrashing around!  As always, please ask if you 
have additional questions.