diff --git a/NixOS.md b/NixOS.md
index b3690f9..077f48c 100644
--- a/NixOS.md
+++ b/NixOS.md
@@ -34,6 +34,29 @@ This document contains general notes about NixOS that are independent of my NixO
 * There is controversy about flakes, rather use channels (e.g. with niv)
 * Prins, P., Suresh, J. and Dolstra, E., "Nix fixes dependency hell on all Linux distributions," [Archived](https://web.archive.org/web/20081226010942/http://www.linux.com/feature/155922) December 26, 2008, at the Wayback Machine linux.com, December 22, 2008
 
+## Upgrade from 23.05 to 23.11
+
+* https://discourse.nixos.org/t/nixos-23-11-released/36210
+
+Change the tracking branch of nixpkgs from 23.05 to 23.11:
+
+```shell
+niv modify nixpkgs      --branch   nixos-23.11
+niv modify home-manager --branch release-23.11
+```
+
+Update `home.stateVersion` to `home.stateVersion = "23.11";` in order to match the NixOS channel.
+
+Read the release notes. GNOME 45: Notably, Loupe has replaced Eye of GNOME as the default image viewer, Snapshot has replaced Cheese as the default camera application, and Photos will no longer be installed.
+
+Updating with nixos-rebuild boot and rebooting is recommended.
+
+```shell
+niv update && colmena build --on yodaTux -v --show-trace && colmena apply-local --sudo boot
+```
+
+TODO: Update yodaHedgehog and yodaYoga with `boot` (!)
+
 ## niv: Dependency management
 
 * https://nix.dev/tutorials/first-steps/towards-reproducibility-pinning-nixpkgs#dependency-management-with-niv
diff --git a/hosts/pi3bplus/configuration.nix b/hosts/pi3bplus/configuration.nix
index c7ea3e8..a5e0452 100644
--- a/hosts/pi3bplus/configuration.nix
+++ b/hosts/pi3bplus/configuration.nix
@@ -67,11 +67,6 @@
   # accidentally delete configuration.nix.
   # system.copySystemConfiguration = true;
 
-  # This value determines the NixOS release from which the default
-  # settings for stateful data, like file locations and database versions
-  # on your system were taken. It's perfectly fine and recommended to leave
-  # this value at the release version of the first install of this system.
-  # Before changing this value read the documentation for this option
-  # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
-  system.stateVersion = "23.05"; # Did you read the comment?
+  # Most users should never change this value after the initial install, for any reason, even if you’ve upgraded your system to a new NixOS release.
+  system.stateVersion = "23.11";
 }
diff --git a/hosts/yodaHedgehog/configuration.nix b/hosts/yodaHedgehog/configuration.nix
index a26d453..cb04088 100644
--- a/hosts/yodaHedgehog/configuration.nix
+++ b/hosts/yodaHedgehog/configuration.nix
@@ -45,4 +45,7 @@
 
   boot.kernelParams = [];
   boot.kernelPackages = pkgs.linuxPackages;
+
+  # Most users should never change this value after the initial install, for any reason, even if you’ve upgraded your system to a new NixOS release.
+  system.stateVersion = "23.05";
 }
diff --git a/hosts/yodaNas/configuration.nix b/hosts/yodaNas/configuration.nix
index ebf25a3..66f1ae4 100644
--- a/hosts/yodaNas/configuration.nix
+++ b/hosts/yodaNas/configuration.nix
@@ -54,4 +54,7 @@
     "mds=full,nosmt"
   ];
   boot.kernelPackages = pkgs.linuxPackages;
+
+  # Most users should never change this value after the initial install, for any reason, even if you’ve upgraded your system to a new NixOS release.
+  system.stateVersion = "23.05";
 }
diff --git a/hosts/yodaTab/configuration.nix b/hosts/yodaTab/configuration.nix
index f348b64..b23e836 100644
--- a/hosts/yodaTab/configuration.nix
+++ b/hosts/yodaTab/configuration.nix
@@ -54,4 +54,7 @@
 
   boot.kernelParams = [];
   boot.kernelPackages = pkgs.linuxPackages_latest;
+
+  # Most users should never change this value after the initial install, for any reason, even if you’ve upgraded your system to a new NixOS release.
+  system.stateVersion = "23.05";
 }
diff --git a/hosts/yodaTux/configuration.nix b/hosts/yodaTux/configuration.nix
index f18aba2..a629824 100644
--- a/hosts/yodaTux/configuration.nix
+++ b/hosts/yodaTux/configuration.nix
@@ -75,4 +75,7 @@
   # Free/Libre.
   # https://en.wikipedia.org/wiki/Linux-libre
   #boot.kernelPackages = pkgs.linuxPackages-libre;
+
+  # Most users should never change this value after the initial install, for any reason, even if you’ve upgraded your system to a new NixOS release.
+  system.stateVersion = "23.05";
 }
diff --git a/hosts/yodaYoga/configuration.nix b/hosts/yodaYoga/configuration.nix
index 69725cc..0c0ffaa 100644
--- a/hosts/yodaYoga/configuration.nix
+++ b/hosts/yodaYoga/configuration.nix
@@ -32,4 +32,7 @@
     "mds=full,nosmt"
   ];
   boot.kernelPackages = pkgs.linuxPackages;
+
+  # Most users should never change this value after the initial install, for any reason, even if you’ve upgraded your system to a new NixOS release.
+  system.stateVersion = "23.05";
 }
diff --git a/iso-aarch64.nix b/iso-aarch64.nix
index 25c8550..b433f62 100644
--- a/iso-aarch64.nix
+++ b/iso-aarch64.nix
@@ -38,5 +38,5 @@
     (builtins.readFile ./assets/ssh/nitrokey.pub)
   ];
   hardware.enableRedistributableFirmware = true;
-  system.stateVersion = "23.05";
+  system.stateVersion = "23.11";
 }
diff --git a/modules/base.nix b/modules/base.nix
index f6305e5..8f9f6df 100644
--- a/modules/base.nix
+++ b/modules/base.nix
@@ -93,12 +93,4 @@
   # https://nixos.wiki/wiki/Firewall
   # -> Firewall rules may be overwritten by docker, as per https://github.com/NixOS/nixpkgs/issues/111852
   networking.firewall.enable = true;
-
-  # This value determines the NixOS release from which the default
-  # settings for stateful data, like file locations and database versions
-  # on your system were taken. It's perfectly fine and recommended to leave
-  # this value at the release version of the first install of this system.
-  # Before changing this value read the documentation for this option
-  # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
-  system.stateVersion = "23.05"; # Did you read the comment?
 }
diff --git a/modules/freetube.nix b/modules/freetube.nix
index 97130e0..f1971e1 100644
--- a/modules/freetube.nix
+++ b/modules/freetube.nix
@@ -1,12 +1,8 @@
 { config, pkgs, lib, ... }:
 {
-  # TODO: We use unstable until Electron is upgraded to higher than 22, e.g. to 27
-  # permalink: https://github.com/NixOS/nixpkgs/blob/60b9db998f71ea49e1a9c41824d09aa274be1344/pkgs/applications/video/freetube/default.nix#L1
-  # current master: https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/video/freetube/default.nix#L1
-
   users.users.yoda = {
     packages = with pkgs; [
-      unstable.freetube # YouTube client.
+      freetube # YouTube client.
     ];
   };
 
diff --git a/modules/home-manager.nix b/modules/home-manager.nix
index 88c391d..209eae0 100644
--- a/modules/home-manager.nix
+++ b/modules/home-manager.nix
@@ -20,13 +20,13 @@ in
   home-manager.useGlobalPkgs = true;
 
   home-manager.users.yoda = { osConfig, config, pkgs, ... }: {
-    /* The home.stateVersion option does not have a default and must be set */
-    /* https://nixos.wiki/wiki/FAQ/When_do_I_update_stateVersion */
-    home.stateVersion = "23.05";
+    # https://nixos.wiki/wiki/FAQ/When_do_I_update_stateVersion
+    # Switching to a higher state version typically requires performing some manual steps, such as data conversion or moving files.
+    home.stateVersion = "23.11";
   };
   home-manager.users.root = { osConfig, config, pkgs, ... }: {
-    /* The home.stateVersion option does not have a default and must be set */
-    /* https://nixos.wiki/wiki/FAQ/When_do_I_update_stateVersion */
-    home.stateVersion = "23.05";
+    # https://nixos.wiki/wiki/FAQ/When_do_I_update_stateVersion
+    # Switching to a higher state version typically requires performing some manual steps, such as data conversion or moving files.
+    home.stateVersion = "23.11";
   };
 }
diff --git a/modules/joplin-desktop.nix b/modules/joplin-desktop.nix
index c27695f..ed99258 100644
--- a/modules/joplin-desktop.nix
+++ b/modules/joplin-desktop.nix
@@ -1,17 +1,10 @@
 { config, pkgs, lib, ...}:
 {
-  # TODO: Similar to signal-desktop, joplin-desktop crashes frequently on Wayland.
-  # As of 2023-10-20, the stable version did not start, but unstable does.
-
   environment.sessionVariables.NIXOS_OZONE_WL = lib.mkIf (config.services.xserver.displayManager.gdm.wayland) "1";
 
   users.users.yoda = {
     packages = with pkgs; [
-      (
-        if (config.services.xserver.displayManager.gdm.wayland)
-        then unstable.joplin-desktop # Markdown notes
-        else joplin-desktop # Markdown notes
-      )
+      joplin-desktop # Markdown notes
     ];
   };
 }
diff --git a/modules/obsidian.nix b/modules/obsidian.nix
index 4f17a4c..2857da5 100644
--- a/modules/obsidian.nix
+++ b/modules/obsidian.nix
@@ -4,9 +4,9 @@
     "obsidian"
   ];
 
-  # TODO: Disallow insecure Electron version electron-24.8.6.
+  # TODO: Disallow insecure Electron version.
   nixpkgs.config.permittedInsecurePackages = [
-    "electron-24.8.6"
+    "electron-25.9.0"
   ];
 
   users.users.yoda = {
diff --git a/modules/pmbootstrap.nix b/modules/pmbootstrap.nix
index c634012..0b07ceb 100644
--- a/modules/pmbootstrap.nix
+++ b/modules/pmbootstrap.nix
@@ -2,10 +2,7 @@
 {
   users.users.yoda = {
     packages = with pkgs; [
-      # As I got the error below, I switched to the unstable version:
-      #   You are using pmbootstrap version 1.50.1, but version 1.53.0 is required.
-      #   Please update your pmbootstrap version (with your distribution's package manager).
-      unstable.pmbootstrap
+      pmbootstrap
     ];
   };
 
diff --git a/modules/signal-desktop.nix b/modules/signal-desktop.nix
index 9eddb5a..845d116 100644
--- a/modules/signal-desktop.nix
+++ b/modules/signal-desktop.nix
@@ -5,11 +5,6 @@
       signal-desktop-beta # Signal client
     ];
   };
-#  users.users.yoda = {
-#    packages = with pkgs.unstable; [
-#      signal-desktop-beta # Signal client
-#    ];
-#  };
 
   # TODO: lib.mkIf (config.services.xserver.displayManager.gdm.wayland)
 
@@ -44,16 +39,4 @@
      });
    })
  ];
-#  nixpkgs.overlays = lib.mkIf (config.services.xserver.displayManager.gdm.wayland) [
-#    (self: super: {
-#      unstable.signal-desktop-beta = super.unstable.signal-desktop-beta.overrideAttrs (old: {
-#        preFixup = old.preFixup + ''
-#          gappsWrapperArgs+=(
-#            --add-flags "--enable-features=UseOzonePlatform"
-#            --add-flags "--ozone-platform=wayland"
-#          )
-#        '';
-#      });
-#    })
-#  ];
 }