{
  description = "Synapse packaging for Deuxfleurs";

  # nixpkgs 22.05 at 2022-11-29
  inputs.nixpkgs.url = "github:nixos/nixpkgs/fecf05d4861f3985e8dee73f08bc82668ef75125";

  outputs = { self, nixpkgs }:
  let
    pkgs = import nixpkgs {
      system = "x86_64-linux";
    };
    pypkgsOverlay = import ./python-packages.nix {
      inherit pkgs;
      fetchurl = builtins.fetchurl;
      fetchgit = pkgs.fetchgit;
      fetchhg = pkgs.fetchhg;
    };
    pkgs2 = import nixpkgs {
      system = "x86_64-linux";
      overlays = [
        (self: super: {
          python3 = super.python3.override {
            self = self.python3;
            packageOverrides = pypkgsOverlay;
          };
        })
      ];
    };
    synapseWithS3 = pkgs2.matrix-synapse.overridePythonAttrs (old: rec {
      propagatedBuildInputs = old.propagatedBuildInputs ++ [
        pkgs2.python3.pkgs.synapse-s3-storage-provider
      ];
    });
  in
  {
    packages.x86_64-linux.default = synapseWithS3;
    #packages.x86_64-linux.default = pkgs2.python3.pkgs.synapse-s3-storage-provider;
  };
}