// 5. 初始化微信支付
$this->instance = Builder::factory([
    'mchid' => $this->mchid,
    'serial' => $this->serialNo,
    'privateKey' => $merchantPrivateKey,
    'certs' => [
        // $platformCertificateSerial => $onePlatformPublicKeyInstance, // 平台证书
        $platformCertificateSerialOrPublicKeyId => $wechatpayPublicKey,  // 支付公钥
    ],
    'secret' => $this->apiV3Key,
]);

$resp = $this->instance->chain('v3/pay/transactions/native')
    ->post(['json' => [
        'appid' => $this->appid,
        'mchid' => $this->mchid,
        'description' => $params['description'],
        'out_trade_no' => $params['out_trade_no'],
        'notify_url' => $params['notify_url'],
        'amount' => [
            'total' => $params['amount'],
            'currency' => 'CNY'
        ],
    ],
        'headers' => [
            'Accept' => 'application/json'
        ]
    ]);

使用的php sdk 1.4版本从平台证书转换为支付公钥。post请求时会抛出异常

Cannot found the serial(`1F81026B4B*******************`)'s configuration, which's from the response(header:Wechatpay-Serial), your's PUB_KEY_ID_011340*******************. 200 OK

微信平台后台已经打开了灰度开始切换公钥