diff --git a/README.md b/README.md
index ee1a784..64f857f 100644
--- a/README.md
+++ b/README.md
@@ -16,6 +16,7 @@ Check which Java toolchains can be found by Gradle:
 - `shell1.nix` -> works 🥳
 - `shell2.nix` -> broken (as well for `gradle javaToolchains`)
 - `shell3.nix` -> works 🥳
+- `shell4.nix` -> works 🥳
 
 This should include version >= 17, e.g.:
 
@@ -40,13 +41,15 @@ Open issue: gradle's toolchain support does not work with IntelliJ
 - `shell2.nix`
   - Another approach - which did no longer work! https://github.com/utybo/Tegral/blob/main/shell.nix
 - `shell3.nix`
-  - This works 🥳
+  - This works with JDK 21 🥳
   - STRG ALT SHIFT s -> SDK -> add JDK ->
     - home path: /usr/lib/openjdk
     - name: usr-lib-jdk
   - STRG ALT s -> build tools -> gradle ->
     - local installation: /usr/lib/gradle
     - Gradle JVM: usr-lib-jdk
+- `shell4.nix`
+  - This works with JDK23 🚀
 
 ### Tasks
 
diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index faa7dd0..71687b0 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -28,7 +28,7 @@ dependencies {
 // Apply a specific Java toolchain to ease working on different environments.
 java {
     toolchain {
-        languageVersion = JavaLanguageVersion.of(22)
+        languageVersion = JavaLanguageVersion.of(23)
     }
 }
 
diff --git a/shell4.nix b/shell4.nix
new file mode 100644
index 0000000..6ab56fb
--- /dev/null
+++ b/shell4.nix
@@ -0,0 +1,25 @@
+# https://discourse.nixos.org/t/how-to-create-a-development-environment-with-intellij-idea-and-openjdk/10153
+{
+  pkgs ? import <nixpkgs> {
+     # https://github.com/NixOS/nixpkgs/issues/166220#issuecomment-1745803058
+     config.allowUnfree = true;
+  }
+}:
+
+let
+  unstable = import (fetchTarball https://github.com/NixOS/nixpkgs/archive/nixos-unstable.tar.gz) { };
+  jdk = unstable.jdk23;
+  gradle = unstable.gradle;
+in
+
+(
+  pkgs.buildFHSUserEnv
+  {
+    name = "foo2";
+    targetPkgs = pkgs_: [
+      pkgs_.jetbrains.idea-ultimate
+      jdk
+      gradle
+    ];
+  }
+).env