From what I was able to observe, the annotation files (CSV) for NetAffx Hg-U133 Plus 2.0 is updated regularly.
However, from glancing at the CSV files (NA35: 2015 & NA22: 2007), I can't seem to notice any glaring difference between the two.
Does anyone know what information is actually being updated? I assume it may be gene identifiers for different databases, but wanted to make sure.
Below are the files I downloaded and examined from Affymetrix website (you need an account to download archived annotation files)
- HG-U133_Plus_2 Annotations, CSV format, Release 22 (20 MB, 5/31/07)
- HG-U133_Plus_2 Annotations, CSV format, Release 35 (33 MB, 4/16/15)