Facebook began testing new designs for its mobile app install ads and page post ads in its iOS app this weekend.

Following an update for Facebook for iOS, some users began to notice that the ads got a bit of a refresh. Page post ads have a new Like button in the corner, potentially making them more effective for fan generation, not just engagement and content marketing. Late last year Facebook changed the way page post ads appear to non-fans so that instead of a call to action to Like the page, the ads promoted interaction on the post itself. Now, these ads do both.

Mobile app install ads have been redesigned to include a “suggested app” label and a profile picture. Previously, app install ads had a banner image only, and this was at the top of the ad, not underneath the ad copy like it is now.

Facebook often tests a number of variations for ads and News Feed stories to determine the best designs for different outcomes. Advertisers aren’t always able to see how their ads look to other users so we try to track these changes for them.

On the company’s fourth quarter earnings call last month, Facebook CEO Mark Zuckerberg said he expected to have to spend a lot more time tinkering with ads in the feed to avoid hurting user experience, but instead Facebook has been able to increase the number of these ads without significantly hurting engagement levels. The addition of advertising in the feed has led to a 1 to 2 percent reduction in Likes and comments, which is less than expected and Zuckeberg says he feels “very confident” about the direction of advertising on the social network.