diff --git a/pkgs/servers/monitoring/prometheus/alertmanager.nix b/pkgs/servers/monitoring/prometheus/alertmanager.nix
index 9402fa44eed2..1e0c152631f9 100644
--- a/pkgs/servers/monitoring/prometheus/alertmanager.nix
+++ b/pkgs/servers/monitoring/prometheus/alertmanager.nix
@@ -2,7 +2,7 @@
 
 buildGoPackage rec {
   pname = "alertmanager";
-  version = "0.20.0";
+  version = "0.21.0";
   rev = "v${version}";
 
   goPackagePath = "github.com/prometheus/alertmanager";
@@ -11,7 +11,7 @@ buildGoPackage rec {
     inherit rev;
     owner = "prometheus";
     repo = "alertmanager";
-    sha256 = "1bq6vbpy25k7apvs2ga3fbp1cbnv9j0y1g1khvz2qgz6a2zvhgg3";
+    sha256 = "0zrzyaqs73pz4rmj4xaj15x4n1542m0nb7jqm2j77k07j75r5w41";
   };
 
   buildFlagsArray = let t = "${goPackagePath}/vendor/github.com/prometheus/common/version"; in ''