diff --git a/nixos/modules/services/continuous-integration/hydra/default.nix b/nixos/modules/services/continuous-integration/hydra/default.nix
index 2da10a9a5e2a..30c5550f71c5 100644
--- a/nixos/modules/services/continuous-integration/hydra/default.nix
+++ b/nixos/modules/services/continuous-integration/hydra/default.nix
@@ -242,8 +242,8 @@ in
     environment.variables = hydraEnv;
 
     nix.extraOptions = ''
-      gc-keep-outputs = true
-      gc-keep-derivations = true
+      keep-outputs = true
+      keep-derivations = true
 
       # The default (`true') slows Nix down a lot since the build farm
       # has so many GC roots.
diff --git a/nixos/modules/services/misc/nix-daemon.nix b/nixos/modules/services/misc/nix-daemon.nix
index ff4e4f5b97d5..c1754c0e0ecb 100644
--- a/nixos/modules/services/misc/nix-daemon.nix
+++ b/nixos/modules/services/misc/nix-daemon.nix
@@ -152,8 +152,8 @@ in
         type = types.lines;
         default = "";
         example = ''
-          gc-keep-outputs = true
-          gc-keep-derivations = true
+          keep-outputs = true
+          keep-derivations = true
         '';
         description = "Additional text appended to <filename>nix.conf</filename>.";
       };