On Mon, Oct 29, 2018 at 12:30 PM Steve Johnson <scj@yaccman.com> wrote:
We actually had a pretty good system for making changes like that.  First, we would change
the compiler to accept both the old and the new.   Then we would produce a warning
that on a particular date the old would no longer work.  Then we made the old an error
and printed a message about how to fix it.   Eventually, we just let it be a syntax error.
This process was applied many times on the way from typeless B to strongly typed C.

How long a transition period did you typically have?