The problem with IDLE is that it requires one TCP connection per folder you want to watch. The better alternative is NOTIFY, but in my experience, it is not as

The problem with IDLE is that it requires one TCP connection per folder you want to watch. The better alternative is NOTIFY, but in my experience, it is not as widely supported by server and client implementations. https://tools.ietf.org/html/rfc5465 https://tools.ietf.org/html/rfc5465