JMIR was a pioneer in developing a workflow and questionnaires to peer-review apps (rather than papers about apps, JMIR mHealth offered a peer-review of the actual app), as early as in 2013, see announcements here and here.
However, after an early trial it became clear that the original business model - developers or owners of apps paying for a peer-review - was problematic for a variety of reasons. Most importantly, it raises conflicts of interest issues, as the funder/sponsor of the reviews should be different from the sponsor of the app. Even if it would be possible to build a "Chinese wall" between the reviewers/editors of the app and the sponsor/developer, it would still at the very least lead to a "perceived" conflict of interest, and positive reviews will appear to be "bought". It also suppresses the publication of negative or more critical reviews.
For this reason, the peer-review trial has been put on hold indefinitely, until a sponsor or alternative funding model can be found (any organizations interested in sponsoring app-reviews, please contact us by filing a ticket a firstname.lastname@example.org).
In the meantime, we accept and publish reviews/comparisons of multiple apps by independent investigators, published in our e-collection 'Quality Evaluation and Descriptive Analysis of Multiple Existing Mobile Apps', which - to our knowledge - is the most comprehensive collection of peer-reviewed papers describing and comparing mHealth apps in the world.