iOS/Android: Instagram has been updated with an improved commenting system, the ability to share likes to your Facebook page, and new profile and explore tabs.
The most evident change is the new explore tab that takes the place of the popular tab. Now alongside whichever photos are trending you can also search directly for users or hashtags of events. The other big change is the ability to share your Instagram "likes" directly to your Facebook page. You can enable this feature in your settings (Profile > Sharing Settings > Facebook). Finally, alongside a few other subtle improvements, the commenting system was cleaned up so you can actually see the full text of what you're typing. The updates are free for both Android and iOS users.