I tried the same thing using iReport 4.6.0: set compatibility to 4.0.1 (options are that or 4.5), opened a report that works on JasperReports 4.1.1, added a few characters to a text field, saved and diffed the file with a copy of the original. Not only did it add the UUID business, it also made many other changes throughout the report, removing classes, changing tags, etc. I reverted to iReport 4.5.1, set compatibility to latest. Then upon save no UUID was added and the report ran fine on 4.1.1. -Sam