This update is highly recommended for users of Nokia S40 feature phones with limited memory, such as the popular Nokia 5130 XpressMusic, Nokia 6300 and Nokia 2700 handsets. This upgrade will also benefit phones with a small screen size, such as the Sony Ericsson K550i and Sony Ericsson W810i phones.
In addition, Opera Mini 5.1 will improve the browsing experience for those who have encountered out-of-memory issues or the need to reload open web pages while surfing with Opera Mini 5. The update is not critical for Opera Mini users on smartphones or high end devices.
Download it on your PC by visiting http://www.opera.com/mobile/download/pc/ or download it from your mobile by visiting m.opera.com