ErrorException in SyncRestHandler.php Undefined index: Content-Type

[fr8train-homebase]

SyncRestHandler.php@274 References CoreConstants::CONTENT_TYPE which is

/**
     * The Content Type String.
     * @var string CONTENT_TYPE
     */
    const CONTENT_TYPE = "Content-Type";

My version of php_curl uses lowercase meaning that php curl is expecting "content-type" at this location in the code, as well as others I'm assuming.

PHP Curl Version (JSON Object) { "version_number": 476160, "age": 5, "features": 12568477, "ssl_version_number": 0, "version": "7.68.0", "host": "x86_64-pc-linux-gnu", "ssl_version": "OpenSSL/1.1.1f", "libz_version": "1.2.11", "protocols": [ "dict", "file", "ftp", "ftps", "gopher", "http", "https", "imap", "imaps", "ldap", "ldaps", "pop3", "pop3s", "rtmp", "rtsp", "scp", "sftp", "smb", "smbs", "smtp", "smtps", "telnet", "tftp" ] }

Currently still a problem on "quickbooks/v3-php-sdk": "dev-master"