Initially, Paint.net was released under a modified version of the MIT License, with the exclusion of the installer, text, and graphics. It was completely open-source, but because breaches of license, all resource files (such as interface text and icons) were released under a non-free Creative Commons license forbidding modification, and the installer was made closed-source. Version 3.36 was initially released as partial open-source, but Brewster later took down the source code, citing problems with plagiarism. In version 3.5, paint.net became proprietary software. Users are now prohibited from modifying it.