Am using the old version of yahoo, how do i update to the latest version?
Generally, You Don't do anything. The Programs such as Yahoo! Do IT without your permission, you log on and an announcement says it has been upgraded, or says you cannot continue until you click "yes" and allow the upgrade. MOST of the actual program is on the Yahoo! server, your computer/phone only has the URL (cookie) access to it.
Yahoo accounts are using the most recent update. You have it each time you log into it.