Composer install: Your requirements could not be resolved to an installable set of packages.

[ghost]

Here is my Cmd-Log:

    composer require jasongrimes/silex-simpleuser
    Using version ^2.0 for jasongrimes/silex-simpleuser
    ./composer.json has been updated
    Loading composer repositories with package information
    Updating dependencies (including require-dev)
    Your requirements could not be resolved to an installable set of packages.

      Problem 1
        - The requested package jasongrimes/silex-simpleuser 1.0.0 could not be found.

    Potential causes:
     - A typo in the package name
     - The package is not available in a stable-enough version according to your minimum-stability setting
       see <https://groups.google.com/d/topic/composer-dev/_g3ASeIFlrc/discussion> for more details.

    Read <https://getcomposer.org/doc/articles/troubleshooting.md> for further common problems.

    Installation failed, reverting ./composer.json to its original content.

Any Idea what causes that problem?

[kontur]

Not a semversion expert myself, but it would seem odd that it's requesting 1.0.0. Have you tried ~2.0 instead?