K-9 MAIL

K-9 Mail is an open-source email client for Android that focuses on privacy, standards compliance, and powerful email management. Key Highlights: • Multi-account management: Unified Inbox for IMAP, POP3, and Exchange accounts. • End-to-end PGP email encryption via OpenKeychain integration. • Real-time Push email notifications via IMAP IDLE. • Per-account signatures, PGP key signatures, and automated folder synchronization rules. • Fully ad-free, respects battery life, and backed by the Mozilla/Thunderbird open-source foundation.