src/Amadeus/Client/Session/Handler/SoapHeader4.php
protected function prepareForNextMessage($messageName, $messageOptions)
    {
        if ($this->isAuthenticated === true && is_int($this->sessionData['sequenceNumber'])) {
            $this->sessionData['sequenceNumber']++;
        }

        $headers = $this->createSoapHeaders($this->sessionData, $this->params, $messageName, $messageOptions);

        $this->getSoapClient($messageName)->__setSoapHeaders(null);
        $this->getSoapClient($messageName)->__setSoapHeaders($headers);
    }
protected function prepareForNextMessage($messageName, $messageOptions)
    {
        if ($this->isAuthenticated === true && is_int($this->sessionData['sequenceNumber'])) {
            $this->sessionData['sequenceNumber']++;
        }

        $headers = $this->createSoapHeaders($this->sessionData, $this->params, $messageName, $messageOptions);

        $this->getSoapClient($messageName)->__setSoapHeaders(null);
        $this->getSoapClient($messageName)->__setSoapHeaders($headers);
    }
Handles authentication & sessions

If authenticated, increment sequence number for next message and set session info to soapheader
If not, set auth info to soapheader

@uses $this->isAuthenticated
@uses $this->sessionData
@param string $messageName
@param array $messageOptions