Add 2.3.1 release notes and download links

site/homepage/content/downloads.md

@@ -21,8 +21,8 @@ for installation instructions.
 
 A command line client for interacting with Hono's north bound APIs and its AMQP adapter is available for download from
 
-* [Eclipse Hono 2.3.0 Command Line Client (Java Archive)](https://www.eclipse.org/downloads/download.php?file=/hono/hono-cli-2.3.0-exec.jar)
-* [Eclipse Hono 2.3.0 Command Line Client (Linux x86_64)](https://www.eclipse.org/downloads/download.php?file=/hono/hono-cli-2.3.0)
+* [Eclipse Hono 2.3.1 Command Line Client (Java Archive)](https://www.eclipse.org/downloads/download.php?file=/hono/hono-cli-2.3.1-exec.jar)
+* [Eclipse Hono 2.3.1 Command Line Client (Linux x86_64)](https://www.eclipse.org/downloads/download.php?file=/hono/hono-cli-2.3.1)
 
 The Java client requires a Java 17 runtime environment to run. The Linux binary should run on most (modern) Linux distributions.
 
@@ -40,5 +40,7 @@ For a list of the changes in this release, take a look at the [release notes]({{
 
 ## Previous versions
 
+* [Eclipse Hono 2.3.0 Command Line Client (Java Archive)](https://www.eclipse.org/downloads/download.php?file=/hono/hono-cli-2.3.0-exec.jar)
+* [Eclipse Hono 2.3.0 Command Line Client (Linux x86_64)](https://www.eclipse.org/downloads/download.php?file=/hono/hono-cli-2.3.0)
 * [Eclipse Hono 2.2.0 Command Line Client (Java Archive)](https://www.eclipse.org/downloads/download.php?file=/hono/hono-cli-2.2.0-exec.jar)
 * [Eclipse Hono 2.2.0 Command Line Client (Linux x86_64)](https://www.eclipse.org/downloads/download.php?file=/hono/hono-cli-2.2.0)

site/homepage/content/release-notes.md

@@ -4,6 +4,30 @@ title = "What is new & noteworthy in Hono?"
 description = "Information about changes in recent Hono releases. Includes new features, fixes, enhancements and API changes."
 +++
 
+## 2.4.0 (not released yet)
+
+### New features
+
+* Hono now supports using Google Pub/Sub as the messaging infrastructure. The Admin Guide and the API documentation have
+  been amended with corresponding information on how to configure Hono and applications for using Pub/Sub.
+* Hono's MQTT and HTTP adapters now support using JSON Web Tokens (JWT) for authentication. In particular, the adapters
+  allow devices that have been connected to Google's IoT Core endpoints to connect to Hono instead. The User Guides have
+  been amended with corresponding information regarding configuration and usage.
+
+### Fixes & Enhancements
+
+* The JDBC based device registry now supports searching for tenants and devices including paging. However, filtering and
+  sorting is not implemented yet.
+
+## 2.3.1
+
+### Fixes & Enhancements
+
+* Using Maven 3.9.x for building Hono was not possible and resulted in an error. This has been fixed.
+* The Device Registry User Guide has been amended with information on how to configure the trust anchor of a tenant
+  using a PEM file.
+* The demo keys and certificates that come with Hono for testing purposes had expired and have been recreated.
+
 ## 2.3.0
 
 ### New features