Can you explain why composer create-project fails if you have a lock file in? I guess it might be an issue if you have a mismatching ICU/intl version compared to the person that ran update. That's an issue in symfony2.3 with the introduction of the icu component. I guess it fixes other problems so it's probably worth it, but it does indeed make it harder to share lock files for OS symfony projects. In companies it's probably ok to force everyone to have the same ICU. /cc @fabpot @bschussek