With every new version of Android there is always going to be a few changes whether it's in the form of new features, or old features being taken away. When Google released the Android M developer preview earlier this Summer at the Google IO developer conference, one of the things most users noticed had disappeared was the option to set notification alerts to be on Do Not Disturb until the next alarm. For those that use alarms frequently enough this was a sad thing to see go, and by all accounts it looked like Google might not ever bring it back as it wasn't introduced in the initial launch of Android 6.0 Marshmallow that started heading out to devices this Fall.
Luckily it looks like Google has re-introduced the function with Android 6.0.1 that started hitting Nexus devices today alongside the 200 new emoji they stated last week would be showing up with this update. If you're on a Nexus device which is receiving the software upgrade to Android 6.0.1 Marshmallow, then you should notice the return of the "until next alarm" option for Do Not Disturb mode as it was there with version of Lollipop. You can of course, still set the Do Not Disturb mode to stay on for a designated amount of time. For example, you can enable it and set it to turn off after an hour or two.
Although this is certainly good news, it really only matters at this point for those already on Android 6.0, or the developer preview, as those are the only users who have seen the removal of the functionality. Anyone still using Android Lollipop still has this feature intact. The potential downside is that OEM devices which don't currently have Marshmallow may end up losing the feature just like Nexus devices only to have to wait for the update to Android 6.0.1 again to get it back, unless they opt to work it in as part of their software touches. Earlier today Google started rolling out the Android 6.0.1 update to compatible Nexus devices, so you may already have the software, and the factory images were posted earlier today as well so you can update to it manually if you have the know-how.