4.0.4 and 6.16.211 is the base official ICS build, so if you were on that before then no there was no OS update.
There was supposed to be an update out mid-August but it appears from this article that it may not actually be released until mid-September. Peep the Link:
My phone just got updated this morning and I'm a bit confused about some of the changes.
I have 4 different email addresses coming into this phone. Before the update, I saw a different icon in the top menu bar for each account so I knew which account I was getting mail from. Now they all use the same icon.
Is there anyway I can get them individualized again?