Keep only the version atribute in derivations, with the full version string of the package. This will make it easier to write a script for automatic updating of the packages using the update-source-version command from common-updater-scripts.
cjdns: https://hydra.nixos.org/build/61134279 jonprl: https://hydra.nixos.org/build/61123711 mate.libmatemixer: https://hydra.nixos.org/build/61126968 dirac: https://hydra.nixos.org/build/61132432 idnkit: https://hydra.nixos.org/build/61123544 trousers: https://hydra.nixos.org/build/61109766 packetdrill: https://hydra.nixos.org/build/61116190 osm2pgsql: https://hydra.nixos.org/build/61118017 nawk: https://hydra.nixos.org/build/61139000