The volume of app downloads rose in April for the first time since January, along with the cost to market those apps. That’s according to the latest figures from app marketing firm Fiksu, which has tracked more than 107 billion app actions on its platform, which helps developers and brands optimize their iOS and Android campaigns.

The company’s app store competitive index, measuring downloads of the top 200 free U.S. iPhone apps, rose 11% in April to 5.61 million daily downloads from 5.02 million in March and 5.2 million in February. However, it was still below the post-holiday peak of 6.1 million downloads in January.

At the same time, the cost to acquire a loyal user -- one who opens an app at least three times after download -- rose by 10%, or 14 cents, to $1.50, from $1.36 in March.

Behind the rise in downloads and costs were a combination three factors, according to Fiksu CEO Micah Adler.

One was continued investment in mobile by brands that kept competition high. Another was the smooth transition from Apple’s unique device identifier (UDID) to its new Advertising Identifer (IDFA) for tracking that avoided disruption. Third was the rapid adoption of Facebook’s mobile app install ads, which increased the pool of efficient inventory and may have saved the industry from an even more rapid increase in costs.