The first upgrade to Microsoft's Internet Explorer in five years hasn't checked the browser's continued -- albeit slow -- decline in market share, a Web metrics firm said Monday.

Even with the introduction of Internet Explorer 7 nearly three weeks ago, Microsoft's share of the browser user base slipped again in October, said Net Applications. "IE continued its market share decline at roughly the same rate it's been experiencing the last few months," said Net Applications in an e-mail accompanying its latest data.

Overall, IE's share slipped from 82.1% in September to 81.3% in October; IE 7 use climbed by just over 1%, but IE 6.0 fell by slightly more than that for the month.

"Microsoft was expected to at least stop losing market share with the new release," said Net Applications. "IE may yet stop the bleeding [but] for the short period in October after both releases, the trends remained the same."

Mozilla's Firefox was updated in October, from version 1.5 to version 2.0. Here, too, said Net Applications, the introduction of a new edition didn't translate into seismic shifts in market share. "Firefox grew at almost exactly the same rate as the previous month, going from 12.5% in September to 13% in October."

Firefox 2.0 debuted Oct. 24.