Preferring to have all the glory stick to Mac OS X, Apple CEO Steve Jobs made no mention of an upgrade to Mac OS 9 during his keynote at San Francisco’s Macworld Expo. However, Apple has quietly released an update from version 9.0.4 to 9.1.

Apple has immediately begun shipping the International-English version of Mac OS 9.1; it’s available to download for Mac OS 9 users.

Designed to ensure a smooth transition to Mac OS X, Mac OS 9.1 serves as the basis for Classic - the technology in Mac OS X that ensures compatibility with today’s application software.

Despite this, Apple states that the Mac OS X Public Beta and Mac OS 9.1 are not compatible. If you install Mac OS 9.1, the Classic environment in the Mac OS X Public Beta will no longer function. OS 9.1 is therefore really aimed at users who switch to the full version of Mac OS X from March 24.

During his keynote, Jobs revealed that Mac OS X will ship as the default operating system on all new Macs after July 2001. Mac OS 9 users will be relieved that Apple will still support them until they decide to make the move to OS X – Apple’s next-generation, Unix-based operating system that is more stable and faster than previous Mac systems.

The Mac OS 9 to Mac OS 9.1 Software Upgrade program is available for anyone who has any version of Mac OS 9. You can obtain the Mac OS 9.1 full install CD for a small charge, for more details, click here.

If you have a high-speed, broadband connection, ( ADSL, Cable modem, leased line) you may download the Mac OS 9.1 update and upgrade any version of Mac OS 9 to Mac OS 9.1 by clicking. If you are connecting to the Internet via a 56K modem, Apple warns that this download could take up to 6-8 hours.

Apple has a Web page giving more information on installing Mac OS 9.1.