usually with big upgrades like that, the persons in charge of the server/application would be fairly vocal to the users. i'm not sure how they are there, though. we went through a 4 month testing phase to work out all the kinks before we deployed it into our production environment.
the best thing you can do is to go ahead and upgrade your OS and be ready for the upgrade when it happens. don't push them too much, either. speaking from the administrator side of things, there's nothing worse than having someone who's not in your department screaming down your throat simply because they want something. you do have a point in requesting the functionality, but there's thousands of dollars involved for upgrading, not to mention even more time and effort and money if they want to do it right (testing, etc). we bought new hardware, a new license, and i personally spent quite a bit of time learning the server environment prior to upgrading. heck, we just spent almost close to $10K on another new server license and user licenses here recently for a third BES.
on monday, why don't you send them an email letting them know how much you appreciate their work and service to you all. just keep it short and sweet. trust me, us administrator types RARELY receive any sort of thanks from anyone, despite having such a big role in almost everything that keeps the company roling along.
Just to add, we had a few people in our organization who knew about the 4.0 version of BES. These were a few of the VPs and Directors.. not many though. From time to time, they asked me how things were coming along, and I simply let them know that I was testing things out with a pool of about 10-15 users (all IT) and to be patient. They were good about the patience part, as we had a few kinks to work out with 4.0. I later on followed up with an email to our entire userbase of BB users and let them know that we would be upgrading the server and touched on a few things (the basic stuff, such as 'it won't affect you one bit, etc'). A week later, I sent out another email letting them know the benefits and functionality gains they would receive if they upgraded their handhelds to OS 4.0 (the wireless PIM sync, etc). About 90% of our users have since upgraded and I've had little to no complaints (and even a few emails of gratiuity).