Perhaps 'version' would have been a better word!
Newer versions (~2004+) have some revised systems including alternate braking, which is now controlled through the ABCU (Alternate Braking Control Unit). Essentially the main difference is that when using the accumulator, the ABCU restricts pedal pressure to 1000psi max (it does this by itself....no more "decrease left" or "decrease right"!).
Another difference effecting this topic is that these versions get nosewheel hydaulic from the yellow system rather than the green in older versions.