From aff9387dd4fbb450bb12c6d4c2c7b97790992531 Mon Sep 17 00:00:00 2001
From: r-vdp <ramses@well-founded.dev>
Date: Sun, 4 Jan 2026 12:37:01 +0200
Subject: [PATCH 1/2] nixos/switchable-system: don't add switch inhibitors by
 default

---
 nixos/modules/services/system/dbus.nix | 8 --------
 nixos/modules/system/boot/systemd.nix  | 4 ----
 2 files changed, 12 deletions(-)

diff --git a/nixos/modules/services/system/dbus.nix b/nixos/modules/services/system/dbus.nix
index a0edb9336208..3751fa5e57fd 100644
--- a/nixos/modules/services/system/dbus.nix
+++ b/nixos/modules/services/system/dbus.nix
@@ -174,10 +174,6 @@ in
         permissions = "u+rx,g+rx,o-rx";
       };
 
-      system.switch.inhibitors = [
-        cfg.dbusPackage
-      ];
-
       systemd.services.dbus = {
         aliases = [
           # hack aiding to prevent dbus from restarting when switching from dbus-broker back to dbus
@@ -216,10 +212,6 @@ in
         cfg.brokerPackage
       ];
 
-      system.switch.inhibitors = [
-        cfg.brokerPackage
-      ];
-
       # Just to be sure we don't restart through the unit alias
       systemd.services.dbus.reloadIfChanged = true;
       systemd.user.services.dbus.reloadIfChanged = true;
diff --git a/nixos/modules/system/boot/systemd.nix b/nixos/modules/system/boot/systemd.nix
index 25bd4c624bfe..7fb5c2259062 100644
--- a/nixos/modules/system/boot/systemd.nix
+++ b/nixos/modules/system/boot/systemd.nix
@@ -567,10 +567,6 @@ in
       );
     };
 
-    system.switch.inhibitors = [
-      cfg.package
-    ];
-
     environment.systemPackages = [ cfg.package ];
 
     environment.etc =

From 1baf74d00f64147eefa73fd30db8b7b95f45feda Mon Sep 17 00:00:00 2001
From: r-vdp <ramses@well-founded.dev>
Date: Sun, 4 Jan 2026 12:41:46 +0200
Subject: [PATCH 2/2] nixos/switchable-system: add release notes to document
 switch inhibitors

---
 doc/release-notes/rl-2605.section.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/doc/release-notes/rl-2605.section.md b/doc/release-notes/rl-2605.section.md
index fc34a120d84d..4e4fcb23afe1 100644
--- a/doc/release-notes/rl-2605.section.md
+++ b/doc/release-notes/rl-2605.section.md
@@ -87,6 +87,8 @@
   If your SQLite database is corrupted, the migration might fail and require [manual intervention](https://github.com/louislam/uptime-kuma/issues/5281).
   See the [migration guide](https://github.com/louislam/uptime-kuma/wiki/Migration-From-v1-To-v2) for more information.
 
+- Switch inhibitors were introduced, which add a pre-switch check that compares a list of strings between the previous and the new generation, and refuses to switch into the new generation when there is a difference between the two lists. This allows to avoid switching into a system when for instance the systemd version changed by adding `config.systemd.package.version` to the switch inhibitors for your system. You can still forcefully switch into any generation by setting `NIXOS_NO_CHECK=1`.
+
 - The `services.nextcloud-spreed-signaling` NixOS module has been added to facilitate declarative management of a standalone Spreed signaling server ("High Performance Backend" for Nextcloud Talk).
 
 - `fetchPnpmDeps` and `pnpmConfigHook` were added as top-level attributes, replacing the now deprecated `pnpm.fetchDeps` and `pnpm.configHook` attributes.