How to provide a pre-release app for a focus group?

Sounds plausible. Thanks. Two additional questions:

1. What is the technical requirement for a repository. I have added them several times to a device, but I have never setup one. Is it a Git repository or just a web server? Is it possible to setup a non-public repository with authentification? We likely publish our project as open source, but not for now.
2. How does the update work? Does the app updates itself with a Qt binding for PackageKit? Do you know an example to learn how to use PackageKit? Is PackageKit a third party library beyond Qt?

1. Me neither, I just know how it works :) I have never done that. Contacting the guy behind OpenRepos (Basil) might be helpfull. OpenRepos works with a repo for each account.

2. Normally manually but you should be able to automate to process using the Package Kit bindings. Storeman's code moght shed some light on this how you can accomplish this.

@Dylan. Thanks. I'll check out the storeman project and ask Basik for the technical requirements. Maybe we could use Openrepos. Maybe he has an idea to offer an app just for specific registered users.

The simplest way I could imagine is by providing a URL where you could download your app and then let the app do the rest (checking for updates etc).

@spag. So I could send the test users an email with a link with the advice to open the list of transferred data in the settings, tap on the app and confirm installation?

For this approach I need to prepare Sailfish on the test devices to accept the source, right? Otherwise the user has to allow foreign software the setting, that is quite dangerous. How could I prepare sailfish to accept a specific source?