let signal-desktop = _: super: { signal-desktop = super.signal-desktop.overrideAttrs ( old: rec { version = "6.34.1"; src = super.fetchurl { url = "https://updates.signal.org/desktop/apt/pool/s/${old.pname}/${old.pname}_${version}_amd64.deb"; hash = "sha256-1kffRXPQmtxIsLZVOgPXDnxUmY59q+1umy25cditRhw="; }; } ); }; in signal-desktop