XryptoMail supports the following features

Push IMAP IDLE and POP support
WebDAV support
Multiple mail accounts support
User OAUTH2 authentication support
Message list sorting by date, arrival, sender, read state etc
Message list with different backgrounds for read state, encryption and stealth etc
Message refiling and flagging
Message view gesture support with Pinch-to-Zoom
Message view/forward with html content support
Message send signature support
Multiple folders support e.g. Gmail
Android runtime app permission request
Dual Theme Support
Multiple languages UI support
GPG & PGP/MIME support using OpenKeychain
Autocrypt Level 1 basic features support
Stealth message with auto deletion on read timeout