Z:gnu-www-ja-free-digital-society--fcb5b4-Now, freedom number 1, the fr/en

Now, freedom number 1, the freedom to study and change the source code to make the program do your computing as you wish, includes something that might not be obvious at first. If the program comes in a product, and the developer can provide an upgrade that will run, then you have to be able to make your version run in that product. If the product will only run the developer's versions, and refuses to run yours, the executable in that product is not free software. Even if it was compiled from free source code, it's not free because you don't have the freedom to make the program do your computing the way you wish. So, freedom 1 has to be real, not just theoretical. It has to include the freedom to use your version, not just the freedom to make some source code that won't run.