This version replaces (no longer appends) the old checksums instead of using those specified by INTEGRITY_CHECK in makepkg.conf. If there are multiple checksums in the PKGBUILD, it will replace the first one and move the new ones to it's place. It also uses a file called "upgpkg" as a scriptlet file (similar to pacman's install files) It can be generated by running upgpkg -g. The functions used could also be defined in the PKGBUILD, but I think that's not really what one should do.
