Twitter looks different. Not wildly so – but enough that you need to pause and take stock of what your'e seeing.
The changes are mostly visual, cosmetic tweaks that Twitter says will make things feel "lighter" and "faster," while also being more friendly to new users. (Twitter actually saw solid growth in the number of users to start 2017, after a couple of years where it struggled to expand its user base.)
Here's a quick look of some of the tweaks.
Twitter's main icons – Home, search, notifications, and DMs – got a redesign. Here are the two next to one another (on the Android app) with the old version on top:
Twitter calls its new icons "more intuitive," and points out another example: The reply button has changed from a little back arrow to a message bubble.
People thought the arrow "meant delete or go back to a previous page," apparently, so they changed it to something more recognizable. Here's the comparison:
Round photos, better typography
Your Twitter avatar is rounded now – both on your profile page and when you see it in a timeline. (It was a square with rounded edges.)
Headlines are also bolder, and the typography made "more consistent" to make things clearer. So here's a then-and-now comparison of this Tomi Lahren-Alaska Airlines exchange that people thought was funny. Old is on the left, new on the right.
Better experience for apps (especially iOS)
iPhone users will be getting a new look with fewer tabs at the bottom of the app (a look that Android has had since last year). Users on iOS will also get links that open directly in a Safari viewer, so they're easier to access.
Meanwhile tweets within apps will auto-update. So any replies, retweets, likes, etc. will show up without having to do anything. This doesn't apply to Twitter.com or Twitter Lite.
For the most part, it's still just Twitter and works pretty much exactly the same. Despite that, don't be surprised if there's constant complaining for 48 hours, before everyone gets used to the changes and in a week, doesn't notice them anymore.