In a welcome, though slightly unusual move, Microsoft has released Internet Explorer 5.1 – currently available only for Mac OS X – for Mac OS 8.1 through 9.2 as well, adding a few minor features and enhancing reliability. The feature set of Internet Explorer 5.1 is largely unchanged from 5.0, adding the few new features that appeared in Internet Explorer 5.1 under Mac OS X. That means that there is a new Interface Extras preferences panel that gives you control over a few cosmetic options, plus whether clicking the Address field selects the text or places the insertion point, whether Internet Explorer opens new windows or uses the front browser window when asked to go to a URL by another application, and whether new browser windows open with the toolbar expanded or use the current default setting. Another useful feature is the Command-Shift-click shortcut that opens the clicked-on link in a new window behind the current one. Also new is support for NTLMv2 authentication in addition to the previous NTLMv1 support. Internet Explorer 5.1 for Mac OS 8.1 through 9.2 requires at least 16 MB of RAM with virtual memory turned on and 12 MB of disk space. It’s a 5.3 MB download.