Support for SHA-2 has improved over the last few years. Most browsers, platforms, mail clients, and mobile devices already support SHA-2. However, some older operating systems such as Windows XP pre-SP3 do not support SHA-2 encryption.
We encourage users running older, less secure systems to upgrade.
This page lists the minimum version required for SHA-2.
Browser SHA-2 Support
| Browser | Minimum Browser Version |
| Chrome | 26+ |
| Firefox | 1.5+ |
| Internet Explorer | 6+ (With XP SP3+) |
| Konqueror | 3.5.6+ |
| Mozilla | 1.4+ |
| Netscape | 7.1+ |
| Opera | 9.0+ |
| Safari | 3+ (Ships with OS X 10.5) |
Operating System SHA-2 Support
| Operating System | SSL Certificate Minimum OS Version |
| Android | 2.3+ |
| Apple iOS | 3.0+ |
| Blackberry | 5.0+ |
| ChromeOS | yes |
| Mac OS X | 10.5+ |
| Windows | XP SP3+ |
| Windows Phone | 7+ |
Above information is excerpted from Digicert.com