Microsoft is officially retiring IE for Mac from the end of January. They plan to stop updates by the end of December and downloads by the end of January

Microsoft plans to discontinue support for its Internet Explorer browser on Mac OS X at the end of this year.
The software developer mothballed the browser, which is currently on version 5.2, in June 2003 after Apple released Safari. Development ever since has been limited to the release of security patches.
Link: Microsoft bids Internet Explorer for Mac farewell - vnunet.com