对于使用Swift的iOS 14.4，我使用了Firebase的示例

For iOS 14.4 using Swift, I used Firebase's example here.

在@ C6Silver的帮助下，建议启用推送通知".在功能"中，我随后可以接收fcm测试通知.

With the help from @C6Silver suggesting to enable "Push Notifications" in Capabilities, I was then able to receive fcm test notifications.

祝大家编码愉快！