diff --git a/README.md b/README.md
index f5ea43c..e79930f 100644
--- a/README.md
+++ b/README.md
@@ -390,7 +390,7 @@ let
       # USB stick, nothing is mistakenly written to persistent storage.
       boot.kernelParams = [ "copytoram" ];
       # Secure defaults
-      boot.cleanTmpDir = true;
+      boot.tmp.cleanOnBoot = true;
       boot.kernel.sysctl = { "kernel.unprivileged_bpf_disabled" = 1; };
 
       services.pcscd.enable = true;