* Released in June 2010
* Based on the Presto layout engine
* Last version to support Windows XP and Mac OS X 10.5 Leopard
* Introduced the "Speed Dial" feature
* Dropped support for Opera Widgets
Opera 17
* Released in April 2013
* Based on the Blink layout engine
* First version to support Windows 8 and Mac OS X 10.8 Mountain Lion
* Introduced the "Discover" feature
* Improved the "Speed Dial" feature
* Added support for extensions
Comparison
| Feature | Opera 12 | Opera 17 |
|---|---|---|
| Layout engine | Presto | Blink |
| Supported operating systems | Windows XP and later, Mac OS X 10.5 Leopard and later | Windows 8 and later, Mac OS X 10.8 Mountain Lion and later |
| Introduced features | Speed Dial | Discover |
| Improved features | Speed Dial | Speed Dial, Discover |
| Added features | None | Extensions |
Conclusion
Opera 17 is a major upgrade over Opera 12. It is based on a more modern layout engine, supports more operating systems, and includes a number of new features. If you are still using Opera 12, I recommend that you upgrade to Opera 17.