Twitter, it is a-changing again. The microblogging service unveiled a new version of its online interface Thursday, with a focus on simplifying the design and making the service easier to use. The new look will roll out on the website in the next few weeks, but it’s available now at Twitter’s mobile website, along with a just-updated Twitter app for iPhone. (The Android app has been updated, too.) The company says it’s “working on updates for other apps, such as Twitter for iPad,” but makes no mention of the Twitter client for Mac.