Uninitialized string offset: 0

[arieffathir]

There is error Uninitialized string offset: 0 in line number Line Number: 238
already change code buffer to "

    $buffer .= chr(0x00);$i++; // Length MSB
    $buffer .= chr(0x04);$i++; // Length LSB
    $buffer .= chr(0x4d);$i++; // M
    $buffer .= chr(0x51);$i++; // Q
    $buffer .= chr(0x54);$i++; // T
    $buffer .= chr(0x54);$i++; // T
    $buffer .= chr(0x04);$i++; // // Protocol Level

Using PHP 7 (Codeigniter)
Using CloudMQTT

Please help.

[xuchl]

maybe like this
$socketContext = stream_context_create(
[
'ssl' => [
'verify_peer_name' => true,
'cafile' => $this->cafile,
'local_cert'=>$this->local_cert,
'local_pk'=>$this->local_pk,
]
]
);