Bug #93958 Connection error: (2054) Server sent charset unknown to the client.

Description:
when I try to execute a connection with the MySql environment, I get the following message: (2054) Server sent charset unknown to the client. Please, report to the developers.

I also identified that the connection of the  Devserver 17 (EasyPHP) software with mysql is quite unstable

How to repeat:
I am using the following software to emulate the server:
Devserver 17.

The code used is the following:

<?php
//Estabelece host, usuario e senha para conexão 
$host="localhost";
$user="root";
$password="Senha";

//Cria o objeto da conexão $conn
$conn = new mysqli($host, $user, $password);

//Se houver erro na conexão encerra todo o processo e exibe mensagem
if ($conn->connect_error){
	die("Erro na conexão: (".$conn->connect_errno.") ". $conn->connect_error);
}

The line errors:
Warning: mysqli::mysqli(): Server sent charset (255) unknown to the client. Please, report to the developers in C:\Users\...\conexao.php on line 8

Warning: mysqli::mysqli(): (HY000/2054): Server sent charset unknown to the client. Please, report to the developers in C:\Users\...\conexao.php on line 8

Hello!

Thank you for the report.
This is duplicate of Bug #85946, please see Bug #85946.

regards,
Umesh

I have already implemented the parameter in my my.cnf file, however the problem continues.

[client]
default-character-set = utf8

[mysql]
default-character-set = utf8

[mysqld]
character-set-server = utf8
collation-server = utf8mb4_unicode_ci