Some servers need an additional IMAP select so new email is reliably received, or is shown as read after it has been read on another device. Selecting this option will cause some increased network traffic.
某些服务器需要额外的 IMAP select 才能可靠的接收新邮件，或者在其他设备上阅读后显示为已读。选择此选项将增加少许网络流量的消耗。