Ab 2016 müssen alle Zertifikate umgestellt werden. Dies sind die minimal Email Clients welche Unterstützt werden.
| Verify SHA-1 Signed E-Mail | Verify SHA-256 Signed E-Mail | Send SHA-1 Signed E-Mail | Send SHA-256 Signed E-Mail | |
|---|---|---|---|---|
| Mozilla Thunderbird 1 - 4 [21] | ? | ? | ? | ? |
| Mozilla Thunderbird 5 - 37 [4] [21] | ? | ? | ? | ? |
| Mozilla Thunderbird 38+ [22] | ? | ? | ? | ? |
| IBM Notes 8 [8] | ? | ? | ? | ? |
| IBM Notes 9 [8] | ? | ? | ? | ? |
| Microsoft Entourage 2004 [17] | ? | ? | ? | ? |
| Microsoft Entourage 2008 [17] | ? | ? | ? | ? |
| Microsoft Outlook 2003 & 2007 on XP SP3 [1] [2] | ? | ? | ? | ? |
| Microsoft Outlook 2007 on Windows Vista [1] [2] | ? | ? | ? | ? |
| Outlook for Mac 2011 [17] | ? | ? | ? | ? |
Minimal Browser Versionen:
 | ab 7.0 und XP SP3 |
 | ab 7.1 |
 | ab 9.0 |
 | ab 3.0 und OS X 10.5 |
 | ab 1.5 |
 | ab 3.5.6 |
 | ab 26.0 |
 | ab 1.4.2 |
+ die neuesten mobilen Geräte, zum Beispiel: | |
 | ab 3.0 |
 | ab 2.3 |
 | ab 7.0 |
 | ab 5.0 |