One feature of Amazon Music allows users to upload their own MP3 files from other sources, but that service is shutting down over the next year or so. According to a help page on Amazon's website, the company will end its Amazon Music Storage subscription service in January 2019. An official date hasn't been released, but once the storage service ends, users won't be able to play or download MP3s they previously uploaded.

Amazon already removed the ability to upload personal MP3s to Amazon Music through its PC and Mac apps earlier this week. The company's dedicated music importer software shuttered even earlier, back in 2015.

Both free and paid customers of Amazon Music Storage will be affected by this recent decision: free users, who were able to upload up to 250 files, can play and download any of that music until January 2019. Free users should download their previously uploaded tracks before January 2019, because those will become inaccessible through Amazon Music at that time.

Paid users, who paid $25 annually to store up to 250,000 files, can also play and download any of that music until their subscription expires. Those who let their subscription expire won't have the option to renew it, and all songs over 250 will be removed. Those remaining 250 songs will be available for one year after the subscription expires before they're removed as well.

Those who stand to lose the most in this situation are paid Music Storage subscribers. Those customers should re-download any and all tracks they originally uploaded before their subscription expires to avoid the service erasing part of their library and leaving them with just 250 songs.

Amazon notes that this change only affects music imported to Amazon Music from other sources. Any music you've purchased from Amazon or uploaded using Amazon's AutoRip service won't be affected. Amazon released AutoRip in 2013 as a way for users to sync CD tracks through MP3 matching, so at least the music that you paid for a long time ago won't be affected by Amazon's move.

Uploading personal MP3s isn't as popular as it used to be thanks to the rise of music streaming services. But at the beginning of the transition, some companies offered ways for customers to listen to their personal MP3 files along with music provided from the new service—Apple has iTunes Match and Google Music has scan-and-match as well. At the time, it was a convenient way for companies to encourage new users to sign on without abandoning the huge music libraries they may have already built up over the years. With more of the music industry moving to paid streaming, it makes more sense for Amazon to focus on its Music and Music Unlimited services.