I like to call it a "religious" upgrade, Red.. you just have to believe it has happened, lol. Seriously though Tmo shows no internal signs for the upgrade, you just will notice some of the new features, such as, being able to open .wav attachments from emails and should also now have two sets of similarly named service books for all email accounts (except your tmo.bb only has one). the attachment endings differ, one has [CICAL], other has [CMIME]. I believe the 2nd book is what allows the different sync ability options on email services that have upgraded to it (like yahoo). I searched a little and the only stuff that comes up with the two together had to do with BES (any BES users feel free to jump in and fill in the blanks in my knowledge).
if you delete all your service books and reregister through handset (and resend down email books from your BIS acct) you should see two sets of similarly named books for each email address and then be able to have two-way sync with yahoo. for me it didn't work so I ended up removing yahoo from my BIS acct and when I reregistered I got a new yahoo mail icon and the two-way sync activated. I tried several times with gmail, but was unsuccessful. I asked around and so far it turns out no other BIS users I've talked to have been able to get gmail to two-way sync.
My theory is BIS 2.3 features, much like 2.1, are a 2 party deal (the two partys being the email provider and the BIS provider) and are not soley dependent on the BIS provider (as they make it seem). e.g. yahoo, you could attach your email acct and go while gmail required you to turn on pop option.
My theory:
As BIS upgrades each version and attaches new features, it's like a baseball catcher learning how to catch new pitches and the signs to go along with it (to signal to the pitcher). The pitcher (the email provider) decides what pitches it feels like learning in its own time frame. Yahoo has now added a curve ball (2 way sync) to it's knowledge of throws. Since BIS now also knows how to catch and signal for this pitch, they are able to use it. GMail right now is like a minor leaguer pitching in the major leagues. the BIS catcher is signaling to GMail to throw the two-way sync, but gmail is waving it off because it does not know that pitch (feature) yet. It is also waving off the email status sync.
I notice my generic pop3 email account (given to me for use on a music site I help run) is much slower delivering my mail (since it seems to poll), rather the instanteous yahoo, which itself advertises it PUSHES email, while officially the only email account that is supposed to have PUSH is the blackberry assigned one (if you are a BIS user). It seems very service related as to how your email accounts will react with BIS. If the email provider knows the pitches, BIS 2.3 will treat you much like BES.
