PPemail offers the common methods to sync your device(s) including IMAP, POP3, SMTP, and SSL/TLS.

Which syncing protocols to use?

IMAP & POP3 are for incoming (getting your email) while SMTP works on the outgoing (sending emails).  SSL/TLS adds a layer of security but may not function properly on older systems.  The best protocol for you depends on how you use email.

Incoming

IMAP: Better when syncing across multiple devices

• • The PPemail server syncs the actions with the email applications across all your devices.
• • Read/delete/move a message on one device and the action syncs across all your devices.
• • Create a subfolder on a desktop, it’s available on your mobile device too.

POP3: Best for keeping account information independent

• • The PPemail server holds the message until a device connects then manages each device independently.
• • Read/delete/move a message on one device and other devices do NOT sync the action.

See a detailed comparison between IMAP & POP3 at Wikipedia

Outgoing

SMTP: Protocol to send outgoing email

• • Can send outgoing email through different servers, usually dependent on location.
• • Use different servers for WiFi, mobile, office, & home 
• • Unsecured (public) servers are convenient but are risky because they expose messages and devices.  Be careful.

Security

SSL/TLS: Required security feature

• • PPemail servers create an encrypted connection thereby preventing messages from being read in transit.
• • Highly recommended to use SSL/TLS
• • Some older systems are unable to connect using it.

Recommendations

For most, the main decision is between POP3 and IMAP.

• • IMAP if prefer to act on an email once across all devices
• • POP3 if use one primary device with occasional checks from secondary devices.

Because security is important, send all emails only through authorised SMTP and enact SSL/TLS.  Update the device’s operating system if the current one prevents it.