Doc update for MySQL 8.4 support

Author: sureshanaparti

source/releasenotes/compat.rst

@@ -38,7 +38,7 @@ Software Requirements
 ~~~~~~~~~~~~~~~~~~~~~
 
 -  Java JRE 17
--  MySQL 8.0 (or equivalent compatible DBMS)
+-  MySQL 8.4 (or equivalent compatible DBMS)
 
 Supported Hypervisor Versions
 -----------------------------

source/upgrading/upgrade/upgrade_notes.rst

@@ -120,8 +120,18 @@ added in CloudStack's db.properties file:
 
    db.usage.driver=jdbc:mysql
 
+MySQL support updated to 8.4
+----------------------------
 
-MySQL 8.0 sql mode change
+As of Apache CloudStack 4.20.3, support for MySQL 8.4 has been added.
+
+Existing deployments upgraded to version 4.20.3 can still continue using MySQL 8.0
+without any changes.
+
+If you are running MySQL 8.0 and would like to upgrade to MySQL 8.4,
+you may follow the standard MySQL upgrade process to migrate safely to version 8.4.
+
+MySQL 8.4 sql mode change
 -------------------------
 
 MySQL mode (sql_mode) has changed in CloudStack db.properties to