To install the apps on phone, access this page from your phone and download app. In case you are using PC, the downloaded file can be saved locally but it will not get installed or used on PC.

Platform
Android 2.x	v3.1	v3.1	v3.1	v3.1
BlackBerry OS6	v3.1	v3.1	v3.1	v3.1
BlackBerry pre OS6	v2.1	v2.1	v2.1	v2.1
iOS	v3.1	v3.1	v3.1	v3.1
J2ME	v2.1	v2.1	v2.1	v2.1

Remove old version from the phone before installing new. To backup your data, synchronize it to website and make sure that it is visible properly in your web account. New install will clear out the old application data on phone.