Hello,
Instagram published in their blog today that: https://instagram-press.com/blog/2018/03/22/changes-to-improve-your-instagram-feed/
"Today we’re introducing changes to give you more control over your feed and ensure the posts you see are timely.
We’ve heard it can feel unexpected when your feed refreshes and automatically bumps you to the top. So today we’re testing a “New Posts” button that lets you choose when you want to refresh, rather than it happening automatically. Tap the button and you’ll be taken to new posts at the top of feed — don’t tap, and you’ll stay where you are. We hope this makes browsing Instagram much more enjoyable.
Based on your feedback, we’re also making changes to ensure that newer posts are more likely to appear first in feed. With these changes, your feed will feel more fresh, and you won’t miss the moments you care about. So if your best friend shares a selfie from her vacation in Australia, it will be waiting for you when you wake up.
Over the next few months, we’ll be sharing more about improvements we’re making to feed. Our goal is to be the best place to share and connect with the people and interests that matter most to you."
Sounds like they will be making it chronological and this other optimized feed as well. Of course it probably wont be the old chronological order timeline, and they are just saying that newer posts are more likely to show up first (more-so than now). Only time will tell what it actually looks like and if it is similar to the glory days again!