Apple releases iOS 11.4.1, HomePod 11.4.1, tvOS 11.4.1 & watchOS 4.3.2 [u]
Apple on Monday released iOS 11.4.1, HomePod 11.4.1, watchOS 4.3.2 and tvOS 11.4.1, cleaning up most of its major platforms. The iOS update is of particular interest for security conscious users, as it marks the first publicly available firmware to include Apple's new USB Restricted Mode.

All four updates are maintenance releases, smoothing out bugs, performance, and security issues. iOS 11.4.1 can be installed through iTunes, or by using iOS 11's over-the-air Software Update feature. Any associated HomePods should be updated to their new firmware automatically.
Installing watchOS 4.3.2 involves loading the Watch app on a paired iPhone, selecting General, then Software Update. The update process requires that an Apple Watch have at least 50 percent charge, and be sitting on its charger as well as within Bluetooth range.
tvOS 11.4.1 can be installed on the Apple TV or Apple TV 4K. If a set-top isn't set to update automatically, the process can be forced by going into the Settings app, System, and then Software Update.
The only detailed release notes are those for iOS 11.4.1, which indicate that it fixes AirPod tracking in Find My iPhone, and improves the reliability of mail, contact, and note sync for Microsoft Exchange. Anecdotal evidence suggests the update may also solve battery drain some people have experienced.
More importantly, the update incorporates USB Restricted Mode, a security feature that effectively disables hardwired USB data connections to protect user information.
Outside of these, the developer and public beta releases suggested the update would concentrate more on bug fixes and performance improvements, rather than introducing new features. It is likely that Apple would rather save any new additions for iOS 12, tvOS 12, and watchOS 5, which are undergoing beta testing ahead of an expected release this fall.
AppleInsider is looking through the latest operating system releases for any changes, and will report back any findings soon.
Updated with information regarding USB Restricted Mode.

All four updates are maintenance releases, smoothing out bugs, performance, and security issues. iOS 11.4.1 can be installed through iTunes, or by using iOS 11's over-the-air Software Update feature. Any associated HomePods should be updated to their new firmware automatically.
Installing watchOS 4.3.2 involves loading the Watch app on a paired iPhone, selecting General, then Software Update. The update process requires that an Apple Watch have at least 50 percent charge, and be sitting on its charger as well as within Bluetooth range.
tvOS 11.4.1 can be installed on the Apple TV or Apple TV 4K. If a set-top isn't set to update automatically, the process can be forced by going into the Settings app, System, and then Software Update.
The only detailed release notes are those for iOS 11.4.1, which indicate that it fixes AirPod tracking in Find My iPhone, and improves the reliability of mail, contact, and note sync for Microsoft Exchange. Anecdotal evidence suggests the update may also solve battery drain some people have experienced.
More importantly, the update incorporates USB Restricted Mode, a security feature that effectively disables hardwired USB data connections to protect user information.
Outside of these, the developer and public beta releases suggested the update would concentrate more on bug fixes and performance improvements, rather than introducing new features. It is likely that Apple would rather save any new additions for iOS 12, tvOS 12, and watchOS 5, which are undergoing beta testing ahead of an expected release this fall.
AppleInsider is looking through the latest operating system releases for any changes, and will report back any findings soon.
Updated with information regarding USB Restricted Mode.
Comments
I never noticed any change in bass or sound quality - it still sounds amazing. Unfortunately, I'm still waiting for a firmware that fixes the regular "hard of hearing" issue that occurs within a day or two after each restart. Like clockwork, Siri becomes almost deaf. Unplugging and replugging the device temporarily restores proper operation. After hours of troubleshooting, Apple's solution was a refund. I bought one locally and it does exactly the same thing.
https://www.reddit.com/r/HomePod/comments/7wu97o/siri_suddenly_lost_its_ability_to_hear_me/
https://www.reddit.com/r/apple/comments/7y79rm/deaf_homepod_in_need_of_a_hearing_aid/
This user reports a similar problem and claims that today's update fixed it for him. I had hoped that for the last two updates, but it always works perfect for a day or two after a restart, so it's still too soon to tell for me.
Usually I'm in the same boat as you, with no battery issues, but this time even my iPhone X, a friends' iPhone 7, and another iPhone 6s Plus, all had MASSIVE drain, even though they were updated in full via iTunes and not OTA. Utilities to check SoC load on these phones showed CPU idle had increased from averages of 1.8-3% had jumped to 10-20%, so don't tell me this isn't an issue.
11.4.1 on my iPX seems ok, but too soon to tell if the battery is better, will have to wait and see.
Give it a few hours (or even the next day) and see if that CPU idle isn't back to "normal".
Always wait a while before updating. Read the reports here, then decide in a few days. And then be prepared for problems. I won't update my watch during the week.
Then I saw a news report this morning about others having battery issues with 11.4.1.
I’d follow Eightzero’s advice - wait a week or two to update. There’s nothing huge in this update. Everyone is making a big deal of the USB restricted mode, but how many people really need to worry about Cellebrite hacking their phone?
This from this very article:
"All four updates are maintenance releases, smoothing out bugs, performance, and security issues. iOS 11.4.1 can be installed through iTunes, or by using iOS 11's over-the-air Software Update feature. Any associated HomePods should be updated to their new firmware automatically."