K-9 Mail is a free open source email client for the Android operating system.
It supports both POP3 and IMAP mailboxes, as well as IMAP IDLE for real-time notifications, Exchange (with WebDAV) support, multi-folder sync, flagging, filing, signatures, bcc-self, PGP, mail on SD and other useful features.
It also gives the user fine-grained control over push and polling message retrieval behavior, with various configuration options that can be set per account and per folder. Along with control over notifications, with the option to have a separate notification tone for each account, you can also configure a “quiet time” range during which you don’t want any intrusive notifications.
The PGP support is probably the most interesting feature, considering the current climate surrounding personal privacy and security in this digital era. K-9 Mail integrates seamlessly with Android Privacy Guard, which is a free and open source application that lets you encrypt, decrypt and sign files, messages or emails using Public Key Encryption (like OpenPGP)
Proprietary applications it could replace on Android:
- Microsoft Office Outlook
- Gmail app
Learn more and download K-9Mail here!