Fully Supported

All the options work properly. Fallback elements show for image backgrounds and web fonts.

Desktop

Apple Mail 8, 9 & 10

Microsoft Outlook 2007, 2010, 2011, 2013, 2016

Windows 10 Mail

Thunderbird 45

Airmail2

Mobile

Gmail App (Android & iOS)

iPhone (all)

iPad (all)

Web

AOL

Comcast

G Suite

Gmail

Inbox by Gmail

Mail.ru

Office 365

Outlook.com

Web.de

Yahoo! Mail

See Article: Drag & Drop: Office 365 Button Does Not Display The Text

Partial Support For Some Options

Messages display correctly, but some options (with low impact) may not display as expected.

Desktop

Microsoft Outlook 2007, 2010, 2013 - Borders are not fully supported

Mobile

Android 4.4 to 6.0 default email application (this is not Gmail) - Columns don't expand to cover 100% of the available width

Web

Office 365 - Borders are not fully supported

Outlook.com - Borders are not fully supported

Only basic settings works

When sending to these clients, we recommend using text and images in a simple one-column layout.

Desktop

Lotus Notes 7, 8 & 8.5

IBM Notes 9

Outlook 2000, 2002 & 2003