Isn't this what change-control (such as CVS or SourceForge) is for? I would use CHANGES sections for release notes and keep version changes relegated to source control. Otherwise, the source file gets too cluttered up!

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We are the carpenters and bricklayers of the Information Age.

The idea is a little like C++ templates, except not quite so brain-meltingly complicated. -- TheDamian, Exegesis 6

Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.