- Online and Offline mode
In IMAP IDLE mode (Push mail), updates to mailbox are immediate, since connection is kept open with server, waiting for updates in connected folder to come in.
However, IMAP protocol specifies that client (ProfiMail is client) must send “ping” (small message) occasionally, to notify server that client's connection is still alive. IMAP protocol says that this ping time shall be at least every 29 minutes since last communication.
By default, ProfiMail has this ping time set to every 15 minutes, which is battery-optimized value on Android devices (device wakes up periodically at these times anyway).
If you encounter lags in arrival of messages when using Push mail, you may lower this value, for example to 5 minutes. This comes at cost of lowering battery life, but it should solve problem of disconnections from Push mail.