Monday, Apple Incorporated released software updates aimed at patching 21 security vulnerabilities in the company’s Mac OS X operating system, the patches being available via Software Update or Apple Downloads.

Of the updates, seven target fixing flaws for the Mac version of Adobe's Flash player, which Adobe itself patched the previous month in two separate releases.

The Mac OS X 10.5.6 is the sixth update for Leopard, which was originally released in October 2007 and brings forth bug fixes and several improvements for the operating system, as well.

One of these improvements focuses on MobileMe that has now been rendered capable of transferring updates performed on calendars or contact information from the Internet or Apple’s iPhone gadget to the primary Mac in less than one minute.

Other features that the recent update has put forward include enhanced reliability of Address Book syncing with the iPhone or other devices and  improvements to AirPort connections, with a more capable roaming tool in large wireless networks with an Intel-based Mac.

As for the bugs that have been fixed, they include one that has made changing one’s status on iChat to „invisible” via AppleScript to no longer log the user out and solving the issues regarding pasting text from a Microsoft Office document that sometimes used to result in actually pasting an image instead.

In terms of graphics, iChat, Cover Flow, Aperture and iTunes have all undergone improvements, while a graphics distortion problem with certain ATI graphics cards has been patched.