Alternatívy programu Posteo pre Windows S s licenciou s otvoreným zdrojom

• Windows S
  Všetky platformy Windows Mac Linux Chrome OS Android iPhone Apple Watch Android Wear iPad Android Tablet Kindle Fire Windows S Web Self-Hosted Software as a Service (SaaS) Windows Mobile Java Mobile F-Droid S60 Android TV Chrome MetaMask Gmail Amazon Appstore OpenPGP S/MIME DAVdroid
• Licencia Open Source
  Akákoľvek licencia Bezplatná licencia Licencia Open Source Obchodná licencia