Alternativas ao ZeroMail para Windows Mobile com licença gratuita

• Windows Mobile
  Todas as plataformas Windows Mac Linux Chrome OS Android iPhone Android Wear iPad Android Tablet Kindle Fire Windows S Web Self-Hosted Software as a Service (SaaS) PHP Windows Mobile Java Mobile S60 Android TV Chrome OpenPGP S/MIME DAVdroid
• Licença gratuita
  Qualquer licença Licença gratuita Licença Open Source Licença comercial