Mozilla has announced that future versions of the Firefox browser will no longer support Mac OS X 10.4 'Tiger'.
The move is designed to allow Mozilla to move ahead with the development of features not supported by Tiger, said Mozilla engineer Josh Aas on the mozilla.dev.planning mailing list on Friday.
"Mac OS X 10.4 was released in April of 2005 and a lot has changed since then," Aas wrote. "We would like to take advantage of more modern technologies on Mac OS X and 10.4 support has been a hindrance."
He noted that Tiger support is also a drag on Mozilla's competitiveness with rival browsers. "Neither Chrome nor Safari has to deal with this," Aas wrote.
Aas said the proportion of Tiger users has diminished with more recent versions of Firefox. For Firefox 3.5, 24 percent of the users are on Tiger, while the figure dropped to 12 percent for Firefox 3.6.
Mozilla said Tiger users will continue to be supported on Firefox 3.6 until that version reaches its end of service, which Aas said would be "several months" after the release of the next major version of the browser, 4.0, later this year.
The next release will be based on version 1.9.3 of the rendering engine Gecko, and that software will be the first to drop Tiger support, Aas said.
He noted that Mozilla had stopped supporting Tiger in September 2009 but had waited until now to make a final decision.
"We are planning to make the decision to remove 10.4 support final and remove the code from the tree," Aas wrote. "We are often one of the last vendors to continue supporting older Mac OS X releases."