Apple seeded iOS 7.0.3 last month to fix a lot of bugs that were hassling the iOS 7 user base but one still managed to escape. Apple has now started seeding iOS 7.0.4 to fix the FaceTime bug as well.
FaceTime bug was being faced by many users across the world and thus to solve the issue Apple has released iOS 7.0.4 for the iOS 7 users and iOS 6.1.5 for the devices that are not compatible with iOS 7 (thus only for iPod Touch 4th Generation). Apple has also updated the iBooks and iTunes U apps with a completely redesigned UI to complement the iOS 7 interface seamlessly.
Note:- Evad3rs team has verified that updating to iOS 7.0.4 will not kill the possibility of having a jailbreak when it comes out in the future. So you can go ahead and update without worrying.
You can download iOS 7.0.4 and iOS 6.1.5 (along with other versions) IPSW files by clicking here.