==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release):  1.6.4
- Deployed with iRedMail Easy or the downloadable installer? Installer
- Linux/BSD distribution name and version: Ubuntu 22.04
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

I've been getting this error in system generated emails like nightly cron script reports and sieve reported emails. Not sure if this should go to the component maintainers or if this falls under the iredmail aggregate. Nothing is broken, just the warnings are annoying and eventually things will need to be updated to avoid broken things. Also this may help inform others that run across this issue as updates are applied. 

WARNING: MYSQL_OPT_RECONNECT is deprecated and will be removed in a future version.

It stems from a change in mysql last week.

httpx://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-34.html#mysqld-8-0-34-deprecation-removal

The MySQL client library currently supports performing an automatic reconnection to the server if it finds that the connection is down and an application attempts to send a statement to the server to be executed. Now, this feature is deprecated and subject to removal in a future release of MySQL.

The related MYSQL_OPT_RECONNECT option is still available but it is also deprecated. C API functions mysql_get_option() and mysql_options() now write a deprecation warning to the standard error output when an application specifies MYSQL_OPT_RECONNECT. (WL #15766)