Blazquez wants the release notes from Apple's servers. However, the release would violate the Terms of Service.
iCloud News Not in iOS 11.3
In any case, the list indicates that a feature that was announced some time ago (WWDC 2017), news about iCloud, will not be integrated into iOS 11.3. It was turned on and off repeatedly during beta testing just for testing purposes. In the editorial we noticed strange behavior across devices. Partly missing then on the tablet pieces of a conversation history, but on the Mac was present.
Apple wants to introduce "News on iCloud" in response to inadequate message synchronization across devices. Apparently, this is not as easy as expected.
AirPlay 2 not yet
We already knew that AirPlay 2 would not be integrated with iOS 11.3. This has become apparent in recent months. Apple tested the functionality in January in the first publicly available beta versions of iOS 11.3 and tvOS 11.3. But already in February participants of the public beta were no longer able to access the function. Therefore, you will have to wait a while for multiroom audio with the HomePod or other AirPlay speakers.
iOS 11.3 has not been released at this time. However, there are many indications that there will be a release this week. Last but not least, the sale of the new iPad, which ships with iOS 11.3, will start.