Alternativas ao Mailsmith para PortableApps.com com licença de código aberto

• PortableApps.com
  Todas as plataformas Windows Mac Linux Chrome OS Android iPhone Apple Watch iPad Android Tablet Windows S Web Self-Hosted BSD Xfce Haiku PortableApps.com Slack F-Droid Ruby Gmail GNOME Cloudron Amazon Echo (Alexa Voice Service) PureOS (Purism)
• Licença Open Source
  Qualquer licença Licença gratuita Licença Open Source Licença comercial