Update: The Day One patch is now live, weighing in at just under 5GB in size. If you're already playing Anthem, you should be able to download it now, and if you're waiting for the full release, you'll get it when you get it.
Anthem was already out to Origin Access subscribers and everyone who had preordered when BioWare said that a "day one" patch would be released for the game on February 22, when it becomes available to everyone who wants it. Today, however, lead producer Ben Irving revealed during a livestream that it will be coming sooner than that—as in, today.
"We're actually going to deploy the patch here in a few hours," Irving said. "We're going to do it with zero downtime, is the plan. And then we'll issue some comms for people to log out of the game and get the new patch and go back in, get on the latest servers so you can keep playing. We're excited to get that out a day ahead of worldwide launch."
The full patch notes have been posted to Reddit. Loading times for older hard drives will be decreased, which is big, and there will also be fixes for "many" infinite loading screens, challenges that weren't tracking properly, and disconnection and crash bugs. Numeric modifier indicators have been added to weapons and gear, gear pieces that were missing primer or detonator icons have been fixed up, and the promised improvements to mouse and keyboard controls have been made.
It's a big patch, but it's got a lot of ground to cover: Read our review in progress to find out why. A rollout time hasn't been announced yet but BioWare said it would be live before the midnight launch.