Upgrade iReport from 3.0.0 to 3.7.1 version

I was creating all .jrxml file by using iReport 3.0.开发者_开发问答0 version. Now i want to convert all these file are work in iReport 3.7.1 version.But whenever i have compile these file in 3.7.1 version then detail portion is not display. so how i can upgrade to iReport 3.0.0 version into 3.7.1 version work all jrxml files in proper way.