The switch to clang for some arches was a bit annoying, because suddenly you had to force an update of every package (practically, bumping every package was next to impossible).
The HEADS-UP is that actually there should be *no* heads-up for 6.2. Thanks to sthen@'s prodding, I've just committed a mechanism that will force all binary packages to update on i386/amd64. User-visible parts end up as @version in each package, a new option in pkg_create, and a new component in pkg_info -S signatures. The bump to the version number for i386 and amd64 has been done in bsd.port.mk/arch-defines.mk. As of now, there are no user-visible parts in there (everything is prefixed with _). People running snapshots will soon noticed a "forced update" of the binary packages (sorry for those of you who already ran pkg_add -u -Dinstalled), but at least, "average" users going from release to release won't see a thing. (and we won't have to advertize using -Dinstalled when such a large change happens).