Instagram BETA was announced well over two years ago alongside the Nokia Lumia 1520 and other apps such as Vine, Temple Run 2, and Asphalt 8. Since the app was conceived in 2013, it's been updated exactly once, only fixing some issues that had occurred a few days before.
Most users have left in favor of better Instagram clients such as 6Tag. After all, it's rare to find something that's been in beta longer than Cortana has.
The Italian site WindowsBlogItalia is reporting that a Universal Windows app is coming and that it's close to completion. Here's a video of the app:
The app is also reportedly an iOS port, using the Project Islandwood bridge to bring Objective-C code to the Universal Windows Platform (UWP). The app is currently in closed beta, but it's nice to see a major update coming to the official Instagram client for Windows phones.