I wrote:
To my reading, what you get from Microsoft here is just as risky for us to depend on as what they offered years ago. So, as the FSF pointed out years ago, "It only says that Microsoft will not sue you over claims in patents that it owns or controls. If Microsoft sells one of those patents, there's nothing stopping the buyer from suing everyone who uses the software.".
According to http://endsoftpatents.org/2014/11/ms-net/ End Software Patents (ESP) speculates that "the 2012 'in re Spansion' case in the USA and the judge ruled that a promise is the same as a licence". However, this might not matter because:
- "it's not explicit in the ruling if this still applies when someone else buys the patents" -- http://en.swpat.org/wiki/The_value_of_promises_and_estoppel_defences
- "you’re only protected if you’re distributing the code “as part of either a .NET Runtime or as part of any application designed to run on a .NET Runtime“. So if you add any of the code to another project, then you lose protection and MS reserves the right to sue you or ask for royalties" -- http://endsoftpatents.org/2014/11/ms-net/
- "the protection only applies to a “compliant implementation” of .NET. So if you want to remove some parts and make a streamlined framework for embedded devices, then your implementation won’t be compliant and the protection doesn’t apply to you." -- http://endsoftpatents.org/2014/11/ms-net/
So even if Microsoft's patent promise not to sue is as good as a license, Microsoft's promise has enough problems with it that you're still left with the same result: you're better off not building dependencies on .NET.
