tvOS 11.4.1 can be downloaded over the air through the Settings app on the Apple TV by going to System --> Software Update. Apple TV owners who have automatic software updates turned on will be upgraded to the tvOS 11.4.1 automatically.
As a minor 11.x.x update tvOS 11.4.1 focuses on performance improvements and bug fixes to address issues that were discovered following the release of tvOS 11.4. Apple does not provide release notes for tvOS updates, so we may not know exactly what's included in the new software.
tvOS 11.4.1 is likely to be one of the last updates to the tvOS 11 operating system, as Apple in June introduced tvOS 12, which will be released to the public this fall and is currently available to developers and public beta testers.
tvOS 12 introduces support for Dolby Atmos, a new zero sign-on feature, Password AutoFill from the iPhone, and new aerial screensavers created in collaboration with the International Space Station. More information on tvOS 12 can be found in our tvOS 12 roundup.