With the help of UniTrackerMobile you can now remove all the apps you have needed for your bug tracker. All you need now is an application called UniTrackerMobile.
In the app, you can create a separate account for each bug tracker. These accounts allow you to quickly switch between the different bug trackers.

You can also copy or move bugs or entire projects. And export individual bugs to XML or PDF.

You are in the field and do not have internet access? No problem, you can copy entire projects in the form of PDF files in the local memory and so at any time without watching Internet. In addition, the app also contains its own simple implementation of a bug tracker. So you can also note down bugs in the app without assigning them to a bug tracker.

The first version supports the following bug trackers:
MantisBT, YouTrack, Redmine, Bugzilla, Jira, Pivotal Tracker, OpenProject and Backlog.

Of course, if an important bug tracker is not included in the list, you can always contact me via "Information -> Contact".

Basically, any bug tracker can be integrated, which contains an interface for third-party providers, this may for example be a soap or REST interface.