diff --git a/nix/deployments/nixops.nix b/nix/deployments/nixops.nix
index 3a4ec72..82d6c27 100644
--- a/nix/deployments/nixops.nix
+++ b/nix/deployments/nixops.nix
@@ -46,6 +46,11 @@ in
         SystemMaxUse=100M
         MaxFileSec=7day
       '';
+
+      # servers should not auto-upgrade; it leads to strange behavior when they
+      # reboot, because of creating their own, new, generation outside of
+      # nixops management.
+      system.autoUpgrade.enable = false;
     };
 
   server =
diff --git a/nix/system/xps11/configuration.nix b/nix/system/xps11/configuration.nix
index 90837fa..65f3acb 100644
--- a/nix/system/xps11/configuration.nix
+++ b/nix/system/xps11/configuration.nix
@@ -104,5 +104,4 @@
   # servers. You should change this only after NixOS release notes say you
   # should.
   system.stateVersion = "20.03"; # Did you read the comment?
-  system.autoUpgrade.enable = true;
 }