diff --git a/bypassing-overruling-ssl-configuration/README.md b/bypassing-overruling-ssl-configuration/README.md
index 2090641..e1e2607 100644
--- a/bypassing-overruling-ssl-configuration/README.md
+++ b/bypassing-overruling-ssl-configuration/README.md
@@ -6,7 +6,7 @@ This projects demonstrates bypassing the ssl configuration of mysql-connector-j
 This mechanism will also work with other libraries.
 
 #### Requirements
-- Java 17
+- Java 21
 - Terminal
 - Docker
 
diff --git a/elasticsearch-with-ssl/README.md b/elasticsearch-with-ssl/README.md
index c47645c..b614997 100644
--- a/elasticsearch-with-ssl/README.md
+++ b/elasticsearch-with-ssl/README.md
@@ -1,7 +1,7 @@
 # ElasticSearch with SSL 🔐
 
 #### Requirements
- - Java 17
+ - Java 21
  - Terminal
  - Docker 
  - Eclipse or Intellij IDEA
diff --git a/grpc-client-server-with-ssl/instant-server-ssl-reloading-with-grpc/README.md b/grpc-client-server-with-ssl/instant-server-ssl-reloading-with-grpc/README.md
index 3be4d75..4a4bd1d 100644
--- a/grpc-client-server-with-ssl/instant-server-ssl-reloading-with-grpc/README.md
+++ b/grpc-client-server-with-ssl/instant-server-ssl-reloading-with-grpc/README.md
@@ -14,7 +14,7 @@ The server has currently one way to update the existing ssl material:
 - Databased based, aka database change listener. This option is hosted in a separate module within this repository, see here: [Instant SSL Reloading With Database](https://github.com/Hakky54/java-tutorials/tree/main/instant-ssl-reloading-with-spring-jetty-database)
 
 #### Requirements
- - Java 17
+ - Java 21
  - Terminal
 
 #### Configure SSL Update Service
diff --git a/instant-server-ssl-reloading-with-netty/netty-server/README.md b/instant-server-ssl-reloading-with-netty/netty-server/README.md
index 72c717b..69c17e2 100644
--- a/instant-server-ssl-reloading-with-netty/netty-server/README.md
+++ b/instant-server-ssl-reloading-with-netty/netty-server/README.md
@@ -14,7 +14,7 @@ The server has currently one way to update the existing ssl material:
 - Databased based, aka database change listener. This option is hosted in a separate module within this repository, see here: [Instant SSL Reloading With Database](https://github.com/Hakky54/java-tutorials/tree/main/instant-ssl-reloading-with-spring-jetty-database)
 
 #### Requirements
- - Java 17
+ - Java 21
  - Terminal
 
 #### Configure SSL Update Service
diff --git a/instant-server-ssl-reloading-with-quarkus/README.md b/instant-server-ssl-reloading-with-quarkus/README.md
index 1d41aaf..688afd8 100644
--- a/instant-server-ssl-reloading-with-quarkus/README.md
+++ b/instant-server-ssl-reloading-with-quarkus/README.md
@@ -14,7 +14,7 @@ The server has currently one way to update the existing ssl material:
 - Databased based, aka database change listener. This option is hosted in a separate module within this repository, see here: [Instant SSL Reloading With Database](https://github.com/Hakky54/java-tutorials/tree/main/instant-ssl-reloading-with-spring-jetty-database)
 
 #### Requirements
- - Java 17
+ - Java 21
  - Terminal
 
 #### Configure SSL Update Service
diff --git a/instant-server-ssl-reloading-with-vertx/vertx-server/README.md b/instant-server-ssl-reloading-with-vertx/vertx-server/README.md
index 4eb7482..6f42362 100644
--- a/instant-server-ssl-reloading-with-vertx/vertx-server/README.md
+++ b/instant-server-ssl-reloading-with-vertx/vertx-server/README.md
@@ -14,7 +14,7 @@ The server has currently one way to update the existing ssl material:
 - Databased based, aka database change listener. This option is hosted in a separate module within this repository, see here: [Instant SSL Reloading With Database](https://github.com/Hakky54/java-tutorials/tree/main/instant-ssl-reloading-with-spring-jetty-database)
 
 #### Requirements
- - Java 17
+ - Java 21
  - Terminal
 
 #### Configure SSL Update Service
diff --git a/instant-server-ssl-reloading/README.md b/instant-server-ssl-reloading/README.md
index be757cc..4cd431d 100644
--- a/instant-server-ssl-reloading/README.md
+++ b/instant-server-ssl-reloading/README.md
@@ -13,7 +13,7 @@ The server has two ways to update the existing ssl material:
  - File based aka file change listener, see here for the implementation: [FilesBasedSslUpdateService](server/src/main/java/nl/altindag/server/service/FileBasedSslUpdateService.java)
  - Databased based, aka database change listener. This option is hosted in a separate module within this repository, see here: [Instant SSL Reloading With Database](https://github.com/Hakky54/java-tutorials/tree/main/instant-ssl-reloading-with-spring-jetty-database)
 #### Requirements
- - Java 17
+ - Java 21
  - Terminal
 
 #### Start the server
diff --git a/instant-ssl-reloading-with-spring-jetty-database/README.md b/instant-ssl-reloading-with-spring-jetty-database/README.md
index e21071e..3a7a897 100644
--- a/instant-ssl-reloading-with-spring-jetty-database/README.md
+++ b/instant-ssl-reloading-with-spring-jetty-database/README.md
@@ -14,7 +14,7 @@ It will be calling the database every 10 seconds to get the ssl material. The ss
  - [DatabaseBasedSslUpdateService](src/main/java/nl/altindag/server/service/DatabaseBasedSslUpdateService.java)
 
 #### Requirements
- - Java 17
+ - Java 21
  - Terminal
  - Docker
 
diff --git a/instant-ssl-reloading-with-spring-tomcat/README.md b/instant-ssl-reloading-with-spring-tomcat/README.md
index ce53117..13eec94 100644
--- a/instant-ssl-reloading-with-spring-tomcat/README.md
+++ b/instant-ssl-reloading-with-spring-tomcat/README.md
@@ -14,7 +14,7 @@ The server has two ways to update the existing ssl material:
 - Databased based, aka database change listener. This option is hosted in a separate module within this repository, see here: [Instant SSL Reloading With Database](https://github.com/Hakky54/java-tutorials/tree/main/instant-ssl-reloading-with-spring-jetty-database)
 
 #### Requirements
-- Java 17
+- Java 21
 - Terminal
 
 #### Start the server
diff --git a/two-way-object-serialization/README.md b/two-way-object-serialization/README.md
index 6d9bf5f..40d3842 100644
--- a/two-way-object-serialization/README.md
+++ b/two-way-object-serialization/README.md
@@ -9,7 +9,7 @@ The flow would be like the diagram below:
 ![alt text](https://github.com/Hakky54/java-tutorials/blob/main/two-way-object-serialization/images/flow.png?raw=true)
 
 #### Requirements
- - Java 17
+ - Java 21
  - Terminal
 
 #### Start the server