There are still a lot of people who use feature phones and Google decided to improve the Gmail interface for these phones. The new version is closer to the smartphone UI, but it doesn’t use AJAX, so you have to load a new page every time you perform an action.
“You’ll get a number of improvements that reduce the number of button presses required to read, reply and compose emails. For example, you can reply directly to a message from the thread view, you can choose to move to the previous or next conversation, and much more,” explains Google.
Gmail used to have a Java app for feature phones, but this is no longer available, at least not officially. Probably the best option to read your messages on a feature phone is to install Opera Mini and use the mobile Gmail site. Speaking of Opera Mini, you’ll get the same “feature phone” Gmail interface even if you use an iPhone or an Android phone.
Google Operating System