I am developing a commercial, closed-source product. Should i use the 0.4 or 0.5 version of the library?
When you are creating a product for PC, where it is possible for users to update any of your used third-party DLL’s (a requirement for LGPL), you can choose both versions. However if you are shipping a product on a read-only device, such as a console DVD, you must use 0.5 or higher, because the MIT license does not require that users can update anything. However before deciding, do always carefully check the mentioned licenses to make sure that your project doesn’t do something uncommon.