This reverts commit18b306b041. Protobuf releases are generally not very backwards compatible and likely to break lots of stuff. E.g. http://hydra.nixos.org/build/17535340 http://hydra.nixos.org/build/17535640 http://hydra.nixos.org/build/17536998 http://hydra.nixos.org/build/17536170 See alsob851e970da.