It strikes me now, given Subversion's "mature, stable" phase of life, that we should default to backward compatibility.
Change the default to --compatible-version=1.8 (same as =1.14), instead of 1.15 (format 32). Both for "checkout" and "upgrade". The user will need to specify "--compatible-version=1.15" when they want to use new-in-1.15-format features (i.e. pristines-on-demand). We should let this option be specified in the user config (file/registry) too. Makes sense? - Julian
