Alternativer til Mailsmith til Windows S med open source-licens

• Windows S
  Alle platforme 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)
• Open Source-licens
  Enhver licens Gratis licens Open Source-licens Kommerciel licens