is compatible license of GNU GPL Compatible License Type GNU GPL v3 GNU GPL v2 GNU LGPL v2.1 https://www.gnu.org/licenses/license-list.html, accessed 28 June 2016. GNU Lesser General Public License (LGPL) version 2.1 This is the previous version of the LGPL: a free software license, but not a strong copyleft license, because it permits linking with nonfree modules. It is compatible with GPLv2 and GPLv3. We generally recommend the latest version of the LGPL, for special circumstances only. GNU LGPL