diff --git a/nixos/modules/services/continuous-integration/buildbot/master.nix b/nixos/modules/services/continuous-integration/buildbot/master.nix
index 326d2cbd82c..e3da3092d45 100644
--- a/nixos/modules/services/continuous-integration/buildbot/master.nix
+++ b/nixos/modules/services/continuous-integration/buildbot/master.nix
@@ -222,7 +222,7 @@ in {
   };
 
   config = mkIf cfg.enable {
-    users.groups = optional (cfg.group == "buildbot") {
+    users.groups = optionalAttrs (cfg.group == "buildbot") {
       buildbot = { };
     };
 
diff --git a/nixos/modules/services/continuous-integration/buildbot/worker.nix b/nixos/modules/services/continuous-integration/buildbot/worker.nix
index 7613692f0a3..52f24b8cee3 100644
--- a/nixos/modules/services/continuous-integration/buildbot/worker.nix
+++ b/nixos/modules/services/continuous-integration/buildbot/worker.nix
@@ -136,7 +136,7 @@ in {
   config = mkIf cfg.enable {
     services.buildbot-worker.workerPassFile = mkDefault (pkgs.writeText "buildbot-worker-password" cfg.workerPass);
 
-    users.groups = optional (cfg.group == "bbworker") {
+    users.groups = optionalAttrs (cfg.group == "bbworker") {
       bbworker = { };
     };
 
diff --git a/nixos/modules/services/continuous-integration/jenkins/slave.nix b/nixos/modules/services/continuous-integration/jenkins/slave.nix
index 26368cb94e4..3c0e6f78e74 100644
--- a/nixos/modules/services/continuous-integration/jenkins/slave.nix
+++ b/nixos/modules/services/continuous-integration/jenkins/slave.nix
@@ -50,7 +50,7 @@ in {
   };
 
   config = mkIf (cfg.enable && !masterCfg.enable) {
-    users.groups = optional (cfg.group == "jenkins") {
+    users.groups = optionalAttrs (cfg.group == "jenkins") {
       jenkins.gid = config.ids.gids.jenkins;
     };