docs: KDE Plasma only: other desktops don't work yet (README)

CHANGELOG.md

@@ -8,6 +8,7 @@ one per merged pull request.
 ## 2.9.0 - 2026-09-28
 
 - `d30d505` **chore: Version 2.9.0**
+- **docs: KDE Plasma only: other desktops don't work yet (README)**
 - `d73e71d` **docs: README, TECHNICAL and TROUBLESHOOTING for 2.9.0: Steam's System settings, serial number and Wi-Fi backend, --defaults --list, the Steamify ISO**
 - `a72d848` **feat: Steam's OS Version is the SteamOS release Steamify follows (steamos-3.9), its OS Codename steam-machine; About this System keeps "CachyOS Linux" (UseOSReleaseVersion)**
 - `27a4070` **fix: Steam's OS Variant shows Steamify's version (VARIANT_ID=steamify-2.9.0; Steam shows VARIANT_ID, not VARIANT)**

README.md

@@ -78,6 +78,11 @@ What Steamify can do on a Valve Steam Machine:
 ## Requirements
 
 - CachyOS with the KDE Plasma desktop (the default CachyOS Desktop edition)
+
+> **KDE Plasma only.** Steamify works with KDE Plasma and its login managers
+> (plasma-login-manager or SDDM). Other desktops (GNOME, Hyprland, Cosmic,
+> ...) and other display managers don't work yet: the switching between gaming mode
+> and the desktop, the theme and the shortcuts are all built for Plasma.
 - Your normal user account, with permission to use `sudo`
 
 ## Installation