The change was minor — Twitter hadn’t suddenly switched to a serif font or anything like that. But a quick Twitter search showed that I wasn’t the only one who noticed the shift, and my co-workers did, too.

It’s unclear why Twitter changed the font, and the company didn’t immediately reply to a request for comment. (It has dissolved its press office, so I’m not expecting one.) And the company hasn’t posted anything on @TwitterSupport, where it’s shared a lot of recent product updates.

However, some have speculated that Twitter changed the font to make it easier to spot impersonators. Molly White, the author of Web3 is Going Just Great, noticed that zeroes have a slash through them, and it’s also easier to tell the difference between an uppercase letter i and a lowercase letter L, meaning that it might now be harder for bad actors to look legit using those tricks. (If only Twitter had a decent verification system that hadn’t been clumsily changed in such a way that it let impersonators run rampant on the platform, forcing the company to reassemble verification into an even more complex monster.)

For me, I’m only seeing the font on the web and mobile web; on the iOS app, I still have the older font. I’m guessing the new font will make its way to other platforms eventually, so if you’re not seeing it yet, consider this your warning.