"Server sent charset unknown to the client" Error

Linux Apps Tutorials - Herong's Tutorial Examples

∟Running MySQL Database Server on Linux Systems

∟"Server sent charset unknown to the client" Error

This section provides a tutorial example on how to resolve the 'Server sent charset unknown to the client' error received in PHP mysqli_connect() call to MySQL 8.0 running on CentOS 8 systems.

If you are running an older version of PHP on a client computer and tries to connection a MySQL 8.0 running on a CentOS system with the mysqli_connect() function, you will get the "Server sent charset unknown to the client" error:

herong$ php --version
PHP 5.6.30 (cli) (built: Oct 10 2017 20:30:32)

herong$ php test.php
PHP Warning:  mysqli_connect(): Server sent charset (255) unknown
   to the client. Please, report to the developers
   in /Users/herong/test.php on line 10.
PHP Warning:  mysqli_connect(): (HY000/2054): Server sent charset ...

Based on reports on the Internet, the above issue is caused by the default setting of "character_set_client = utf8mb4", which is unknown to older PHP "mysqli" modules.ß

I have tried a number of solutions suggested on the Internet. None of them works for me. Combinations of them are also not working.

Run "set global character_set_client = 'utf8';" on MySQL 8.0 server.
Run "set global character_set_results = 'utf8';" on MySQL 8.0 server.
Run "set global character_set_connection = 'utf8';" on MySQL 8.0 server.
Restart MySQL 8.0 server with the "skip-character-set-client-handshake" option.
Restart MySQL 8.0 server with the "character_set_client=utf8" option.

The only solution that worked for my is to upgrade PHP to

herong$ php --version
PHP 7.2.11 (cli) (built: Oct  9 2018 15:09:36) ( NTS )

herong$ php test.php
mysqli_get_server_info() = 8.0.17
mysqli_get_host_info() = 192.168.1.100 via TCP/IP