Apple stores are said to be planning to remain open all night on Tuesday 24 July - suggesting the OS X Mountain Lion update will be made available on 25 July. claims to have been told that select Apple Stores in both the US and other countries are planning the all-nighters in preparation for Mountain Lion launching the next day.

However, as the new operating system isn’t been launched with any new hardware, is speculating that the overtime will simply involve Apple employees installing Mountain Lion on all the store’s computers on display rather than selling the update via a disc or USB stick.

Apple announced its OS X Mountain Lion at its WWDC event, promising that the operating system would be available in July and a Golden Master version is already with app developers now.

When OS X Mountain Lion does finally arrive, regular Apple users will be able to upgrade via the Mac App Store for $19.99, though some older Macs will not be compatible.

What are you most excited about Mountain Lion? We want to know.