I realize that I've asked this before - but I never got a response which I found convincing. I'll try to ask my question better this time. The question - What is the value of undertaking this task. Let's look at the value of according to the type of boost participant. a) boost user - all this code in config and the libraries is internal to the libraries. After this change the look and usage of boost will not change at all. - no benefit and no cost to the boost user. b) author of a new library - this person can set the requirements to what ever he wants subject to the constaint that the code compile and work on any comforming C++ implementation. That is, there has never been a requirement to support non-conforming or older compilers. This won't change. Only authors who want to support an older compiler would be affected. It's safe to say there aren't many authors in this category. so no benefit and no cost to authors of new libraries. c) boost users on older platforms. They are to be stuck with the boost 1.54. I don't know how big this group is but I'm sure it has some members. A big loss for this (probably small) group as they won't benefit from things like bug fixes and enhancements. d) maintainers of boost libraries. When I first raised this question, I was assured that it would be totally transparent to me and that I would not have to be concerned about it. Hmmm - well OK - as long I don't have to wade in and muck around with ten year old code - (don't even think about addressing any changes which make old data sets unreadable). My worst nightmare is having to go back and re-debug 20 thousand lines of code running on 10 different compilers. Recent postings have made me doubt that one can really undertake this and guarentee that I won't have to do this. Soooooo - bottom line: No benefit to any boost participant Definite costs to some boost users. Possible big problems for library maintainers. So how can this be worth doing? If one sees real value in this - how about creating this on a branch or a fork. Robert Ramey