You see this a lot today. As support for older versions fades, you may have to keep up or do without.
I thought there are alternative browsers for this machine. I don't know which Apple you have but here's the search.
I have an imac running 10.4.11 and up until recently I would look up routes on mapquest and then was able to send them to my Garmin nuvi 750. Now it seems mapquest no longer supports that option. I called garmin who suggested i download basecamp which i have tried to do but the oldest version I can find requires 10.5 or newer. Is there software available that will work with my system? I just want the basics... to and from routes. I am using safari 4.1.3 which i understand is the newest browser available for my operating system. I only do this about a dozen times a year. Any help would be appreciated....Thanks in advance