| Q | A | ---------------- | ----- | Bug report? | yes | Feature request? | no | BC Break report? | yes | RFC? | yes/no | Symfony version | 2.8.16 The error appeared after upgrading composer that upgraded Symfony to version 2.8.16. Falling back to Symfony 2.8.15 "solves" the error. What have I to do? [I opened this same issue on the KNP Menu repository, too.](https://github.com/KnpLabs/KnpMenu/issues/252)