Since Samsung released Android 5.1.1 Lollipop update for Galaxy S6 and Galaxy S6 edge, owners have been complaining of various issues.

One of the most common problems reported by Galaxy S6 and Galaxy S6 edge owners is the reduced battery usage time after upgrading to Android 5.1.1 Lollipop.
There are many other issues with the Galaxy S6 after applying this update, and we have already covered most of them in our previous extensive article.
One thing is worth mentioning though, and that's the fact that all the issues and problems that Galaxy S6 owners are complaining about have nothing to do with Google.
Most Nexus devices that received Android 5.1.1 Lollipop a long time ago do not have the issues that affect the Galaxy S6 and Galaxy S6 edge.
This means that Samsung is the only one to blame for all the problems that Galaxy S6 and Galaxy S6 edge owners are experiencing after the update.
Even though not all devices seem to be affected by these problems, it looks like there's a high amount of Galaxy S6 units suffering from these issues.

The update might arrive at other carriers, too

Today, T-Mobile announced that a new Android 5.1.1 Lollipop update is available for download beginning July 27. Software update G925TUVU2COF8 should provide come improvements and bug fixes, according to the official changelog.
T-Mobile mentions the update does not bring any new features, but adds some battery improvements, as well as a cocktailbar error fix. Last but not least, the latest update also promises various bug fixes and device improvements.
Keep in mind that the update is expected to be delivered worldwide, so depending on region you might receive it sooner or later.
Android 5.1.1 Lollipop update for Samsung Galaxy S6 and Galaxy S6 edge is pushed OTA (over the air) in stages, so it will not be available to everyone at the same time.