diff --git a/README.md b/README.md
index 66412f3..6596347 100644
--- a/README.md
+++ b/README.md
@@ -2,4 +2,14 @@
 
 Upload a file. Share the URL/link. Download the file.
 
-Simple as that.
\ No newline at end of file
+Simple as that.
+
+## Setup development environment
+
+Requirements:
+- Java JDK 21
+- Gradle 8.5
+
+1. Update `spring.profiles.active` in `application.properties` to `development`
+2. Start external Backend and Database
+3. Run `./gradlew bootRun ` in the root directory
\ No newline at end of file
diff --git a/build.gradle b/build.gradle
index 6a61ff9..078791f 100644
--- a/build.gradle
+++ b/build.gradle
@@ -9,6 +9,7 @@ version = '0.0.2'
 
 java {
 	sourceCompatibility = '21'
+	targetCompatibility = '21'
 }
 
 configurations {