Autodesk Sketchbook for Android was released on May 1, 2018, and was one of the first versions where the full-featured app became free for everyone.
If you're looking to download an older version of Autodesk Sketchbook, specifically version 4.1.5, and you've come across a repackaged version, here are some helpful considerations:
: Modern versions of the app are now managed by Sketchbook, Inc. and may require a one-time purchase to unlock "Premium" features that were previously free in the Autodesk era.