Desktop clients
- Air Mail 2.0
- Apple Mail 4
- Apple Mail 5
- Apple Mail 6
- Apple Mail 7
- Apple Mail 8
- Apple Mail 9
- Entourage 2004
- Entourage 2008
- IBM Notes 9
- Lotus Notes 8
- Lotus Notes 8.5
- Outlook (all versions)
- Thunderbird 3.0+
- Windows Live Mail
- Windows Mail
Web-based clients
- AOL Mail
- Atmail Open
- CitroMail.hu
- Comcast
- Daum.net
- FreeMail.hu
- Google Inbox
- Gmail
- GMX
- G Suite
- Libero.it
- Mailbox.hu
- Nate.com
- Naver.com
- Roundcube Webmail
- Outlook.com
- Office 365
- Web.de
- Yahoo! Mail
- Mail.ru
- Yandex Mail
Mobile clients
- Android 2.3 - 4.2.x
- Android 4.3+
- Blackberry 5+
- Daum.net app
- Gmail app
- Inbox app
- iPhone 4 - 8 Plus
- (new) iPhone X
- iPad (retina display too)
- iPad Air
- iPad Mini
- iPad Pro
- KindleFire 2.3
- Nate app
- Outlook App
- Windows Phone 7.5
- Windows Phone 8+
