Instagram had stated that it would change the current chronological order to an algorithm-based approach, again very similar to what Facebook does with its News Feed.
The idea behind the whole thing is to push stuff that the software thinks you would like more to the top of your feed, which means you will probably miss some things as well, obviously.
Based off of the panic and the platform being barraged with follower requests to maintain the status quo, Instagram announced via Twitter that the changes were not coming just yet.
When it initially announced the changes, Instagram said the changes will come in the "coming months". After consumer rage set in, the company reiterated that it would make a formal announcement when the changes do take place.