Здравствуйте, пытаюсь поставить различные расширения от катрика, например: "kartik-v/yii2-mpdf": "dev-master", но composer постоянно выдает ошибку. В данном случае:
Your requirements could not be resolved to an installable set of packages.
Problem 1
- Installation request for kartik-v/yii2-mpdf dev-master -> satisfiable by kartik-v/yii2-mpdf[dev-master].
- Can only install one of: myclabs/deep-copy[1.7.0, 1.6.1].
- Can only install one of: myclabs/deep-copy[1.7.0, 1.6.1].
- Can only install one of: myclabs/deep-copy[1.7.0, 1.6.1].
- Conclusion: install myclabs/deep-copy 1.7.0
- Installation request for myclabs/deep-copy (locked at 1.6.1) -> satisfiable by myclabs/deep-copy[1.6.1].
Installation failed, reverting ./composer.json to its original content.
В чем причина?
