There's a good few lines about that here http://www.mono-project.com/docs/about-mono/releases/4.0.0/#microsoft-source-code-adoption http://www.mono-project.com

There's a good few lines about that here http://www.mono-project.com/docs/about-mono/releases/4.0.0/#microsoft-source-code-adoption http://www.mono-project.com/docs/about-mono/releases/4.0.0/#... of note (to me) is the replacement of significant mono modules with the MS equivalents; Decimal, LINQ, Threading.Tasks, and on - a list that looks like what some people might call the 'tricky bits' ...