Amazon is eventually ending its service that offers cloud storage of MP3 files. The Amazon Music Storage is projected to shut down in January 2019, but an exact date has not been shared yet. Once the service stops, users will not be able to play or download MP3s they previously uploaded to their cloud locker.
There are two important details in this announcement. First, the change will not impact music purchased from Amazon, both as MP3s and as AutoRip from CDs. Amazon-bought music will remain stored for playback and download. Second, the move will impact both the free and paid users of Amazon Music Storage. The help page for Amazon Music Storage has more detail.
As of this week, Amazon no longer lets users upload their personal MP3 library to Amazon Music on its PC and Mac apps. It ended its dedicated music importing software in 2015. The changes all seem to point toward Amazon limiting auxiliary services around its MP3 division and putting more resources into its formal streaming option, Amazon Music Unlimited.