The GPL is a very strict free/open source software license. In order to assure that programs licensed under the GPL retain their freedom, once a program is developed with GPL-licensed code, the developed program must also be licensed under the GPL. Because of this quality, some people call the GPL a “viral” license. That is, as a project makes use of GPL-licensed code, the resulted project will have to adopt GPL as its license. This in turn makes the GPL a license with very low degree of compatibility. A developer has to consider the following conditions:

a. Although the GPL is compatible with the BSD, MIT and zlib/libpng licenses, but the resulted program has to adopt the GPL.
b. The GPL is compatible with the LGPL.
c. There exists a way of conversion between the LGPL and the GPL. The licensee of an LGPL-licensed program can convert the copy of the LGPL-licensed program in question into one that is GPL-licensed. The licensee will have to make necessary modifications to documents related to that program in question so that the recipients will be informed that this reproduction of the program is now licensed under the GPL. The conversion is one-way, which is, once the conversion is made, there is no going back to the LGPL license.