diff --git a/pkgs/development/tools/misc/hydra/default.nix b/pkgs/development/tools/misc/hydra/default.nix
index 42da07baca66..395ab5349c2f 100644
--- a/pkgs/development/tools/misc/hydra/default.nix
+++ b/pkgs/development/tools/misc/hydra/default.nix
@@ -1,7 +1,7 @@
 { stdenv, nix, perlPackages, buildEnv, releaseTools, fetchFromGitHub
 , makeWrapper, autoconf, automake, libtool, unzip, pkgconfig, sqlite, libpqxx
 , gitAndTools, mercurial, darcs, subversion, bazaar, openssl, bzip2, libxslt
-, guile, perl, postgresql, nukeReferences, git, boehmgc
+, guile, perl, postgresql, nukeReferences, git, boehmgc, nlohmann_json
 , docbook_xsl, openssh, gnused, coreutils, findutils, gzip, lzma, gnutar
 , rpm, dpkg, cdrkit, pixz, lib, fetchpatch, boost, autoreconfHook
 }:
@@ -34,8 +34,8 @@ let
         CatalystViewDownload
         CatalystViewJSON
         CatalystViewTT
-        CatalystXRoleApplicator
         CatalystXScriptServerStarman
+        CatalystXRoleApplicator
         CryptRandPasswd
         DBDPg
         DBDSQLite
@@ -71,15 +71,15 @@ let
   };
 in releaseTools.nixBuild rec {
   name = "hydra-${version}";
-  version = "2018-08-07";
+  version = "2019-02-01";
 
   inherit stdenv;
 
   src = fetchFromGitHub {
     owner = "NixOS";
     repo = "hydra";
-    rev = "4dca8fe14d3f782bdf927f37efce722acefffff3";
-    sha256 = "1yas4psmvfp7lhcp81ia2sy93b78j9hiw9a6n3q2m1a616hwpm25";
+    rev = "8b5948f4cf12424c04df67a6eb136c9846fb2cfd";
+    sha256 = "0ldk3li394vykl9c4v9bs8pir05pmad24s0rx9bzqgz569zfj2iv";
   };
 
   buildInputs =
@@ -88,6 +88,7 @@ in releaseTools.nixBuild rec {
       guile # optional, for Guile + Guix support
       perlDeps perl nix
       postgresql # for running the tests
+      nlohmann_json
     ] ++ lib.optionals isGreaterNix20 [ boost ];
 
   hydraPath = lib.makeBinPath (