diff --git a/2021-02/spring-20/spring-20-exercise/pom.xml b/2021-02/spring-20/spring-20-exercise/pom.xml
index f3041e59..71bbd272 100644
--- a/2021-02/spring-20/spring-20-exercise/pom.xml
+++ b/2021-02/spring-20/spring-20-exercise/pom.xml
@@ -11,7 +11,7 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>2.4.4</version>
+        <version>2.2.4.RELEASE</version>
         <relativePath/>
     </parent>
 
diff --git a/2021-02/spring-20/spring-20-solution/pom.xml b/2021-02/spring-20/spring-20-solution/pom.xml
index 5dfdf065..13d66a4f 100644
--- a/2021-02/spring-20/spring-20-solution/pom.xml
+++ b/2021-02/spring-20/spring-20-solution/pom.xml
@@ -11,7 +11,7 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>2.4.4</version>
+        <version>2.2.4.RELEASE</version>
         <relativePath/>
     </parent>
 
diff --git a/2021-02/spring-20/spring-20-solution/src/main/java/ru/otus/spring/rest/AnnotatedController.java b/2021-02/spring-20/spring-20-solution/src/main/java/ru/otus/spring/rest/AnnotatedController.java
index 3d723f35..184da872 100644
--- a/2021-02/spring-20/spring-20-solution/src/main/java/ru/otus/spring/rest/AnnotatedController.java
+++ b/2021-02/spring-20/spring-20-solution/src/main/java/ru/otus/spring/rest/AnnotatedController.java
@@ -13,7 +13,8 @@ public class AnnotatedController {
 
     @GetMapping("/flux/one")
     public Mono<String> one() {
-        return Mono.just("one");
+        return Mono.just("one")
+                .map(String::toUpperCase);
     }
 
     @GetMapping("/flux/ten")