Late last year I mentioned an NSLog replacement with different logging levels, customizable logging formats, and more called XLFacility.
Here’s an open source library that allows you to automatically send NSLog messages from your app running on a user’s device to a specified server called Teleport from Kenneth Jiang.
Teleport includes a basic HTTP based aggregator which you can use as your backend server, or you can extend Teleport to use the aggregator of your choice.
Usage is simple and only requires you to include Teleport in your app delegate.
You can find Teleport on Github here.
A handy library for debugging.