diff --git a/build.gradle b/build.gradle
index 377cebfd..91ea2832 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,7 +1,7 @@
 plugins {
     // Spring boot & dependency management:
     // https://docs.spring.io/spring-boot/docs/current/gradle-plugin/reference/htmlsingle/
-    id 'org.springframework.boot' version '3.5.14'
+    id 'org.springframework.boot' version '4.0.6'
     // https://docs.spring.io/dependency-management-plugin/docs/current-SNAPSHOT/reference/html/
     id "io.spring.dependency-management" version "1.1.7"
     // Lombok generates getter and setter and more. https://projectlombok.org/