We're excited to announce that we've fully migrated the Xbox Forums to their new home, here on the Microsoft Community forums!
As of today, going to forums.xbox.com will redirect you here to the Xbox area of the Community forums. We've moved all of your existing threads over so you can continue and start conversations with the new forums experience.
We sincerely appreciate the feedback you have provided over this transition and can't wait for you to check out the new Xbox Forums!
If you are connected to Xbox Live and you enter the game, you should be immediately prompted to download an update. If you have not received it personally (and you have other people who play Reach on the same console), then it has already been downloaded.
Without updating, you will not be able to play the game while signed into Xbox Live. So you can be sure that if you're able to play online, your console has already received the update.