Instagram's New Update Debuts "Archive" Feature
Available in Instagram version 10.21.

Instagram has been testing an archive option earlier this year. Today, the platform has officially rolled out the feature to the public.
This feature allows users to hide old posts without deleting them by going into the ellipses (…) menu on a photo — usually reserved for editing and deleting posts — where a new option to archive will be found at the top. This will send your photo into a private gallery that only you will see. Followers will not be notified when a post is archived, and you can always return the picture to your feed in chronological order of its original post date.
Users will be able to find their archive gallery on their profile in the form of a rewind button when they download the 10.21 update.