You can restore a previous version of Trade Interceptor, which you have downloaded and used in the past, only if it was backed-up prior to the following update you made.
When updates arrive for your Trade Interceptor application and you install them, they overwrite the previous version on the device. Therefore a backup is vital if you wish to avoid problems that might arise in the new app update.
In order to backup your current Trade Interceptor app you can use some free file manager apps like Astro File Manager for example. There are various file manager apps in the market. Use the backup functionality of the file management app to make a backup of Trade Interceptor app. However you should know that a backup copy will not store your settings in Trade Interceptor app, it will be like a freshly installed app. The backup app will no longer have connection to the market and you will not get an automatic notification when a new update version will be released. You will need to manually check for new pending updates.