Accurate information about the GRE must come directly from GRE. What follows are links to the appropriate pages on the GRE site.
For Test Takers
GRE® General Test (for testing before August 1, 2011)
GRE® revised General Test (for testing on or after August 1, 2011)
For Institutions
GRE Tests (for General Test administrations before August 1, 2011, and for all Subject Tests)
GRE revised General Test (for General Test administrations on or after August 1, 2011)