diff --git a/nixos/modules/services/monitoring/prometheus/alertmanager.nix b/nixos/modules/services/monitoring/prometheus/alertmanager.nix
index 7d790b6b590..31beee3d39d 100644
--- a/nixos/modules/services/monitoring/prometheus/alertmanager.nix
+++ b/nixos/modules/services/monitoring/prometheus/alertmanager.nix
@@ -151,17 +151,15 @@ in {
       systemd.services.alertmanager = {
         wantedBy = [ "multi-user.target" ];
         after    = [ "network.target" ];
-        script = ''
-          ${cfg.package}/bin/alertmanager \
-            ${concatStringsSep " \\\n  " cmdlineArgs}
-        '';
-
         serviceConfig = {
           User = cfg.user;
           Group = cfg.group;
           Restart  = "always";
           PrivateTmp = true;
           WorkingDirectory = "/tmp";
+          ExecStart = "${cfg.package}/bin/alertmanager" +
+            optionalString (length cmdlineArgs != 0) (" \\\n  " +
+              concatStringsSep " \\\n  " cmdlineArgs);
           ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
         };
       };
diff --git a/pkgs/servers/monitoring/prometheus/alertmanager.nix b/pkgs/servers/monitoring/prometheus/alertmanager.nix
index 530c4305088..e104f31a74d 100644
--- a/pkgs/servers/monitoring/prometheus/alertmanager.nix
+++ b/pkgs/servers/monitoring/prometheus/alertmanager.nix
@@ -2,7 +2,7 @@
 
 buildGoPackage rec {
   name = "alertmanager-${version}";
-  version = "0.15.3";
+  version = "0.16.2";
   rev = "v${version}";
 
   goPackagePath = "github.com/prometheus/alertmanager";
@@ -11,12 +11,9 @@ buildGoPackage rec {
     inherit rev;
     owner = "prometheus";
     repo = "alertmanager";
-    sha256 = "037wwfadb9rp1592v8bkqcsy9ym4gbhkg3pz6a6fzirg65d29aia";
+    sha256 = "0zjyr9964qxv5fsb17qhmxa1v4z0c7va60n05p9w6j2ah4dmcd8q";
   };
 
-  # Tests exist, but seem to clash with the firewall.
-  doCheck = false;
-
   buildFlagsArray = let t = "${goPackagePath}/vendor/github.com/prometheus/common/version"; in ''
     -ldflags=
        -X ${t}.Version=${version}