# If an AUR package has not been updated and you need a different version,
# the following notes may be of some help. I had to use this method
# to upgrade from 2.4.0 to 2.5.0 because the 2.4.0 gkrellm package on AUR would
# not build with my current development environment.

# go to where pacman has done its install (lg is my user name.. yours will be different)
cd /var/tmp/pamac-build-lg/gkrellm
ls
# you should see if build file called PKGBUILD
# use your editor of choice to edit the build file
geany PKGBUILD
# now make the 2 changes... 
# change pkgver=2.4.0 to pkgver=2.5.0
# change sha256sums=('6f83665760b936ad4b55f9182b1ec7601faf38a0f25ea1e4bddc9965088f032d')
to
sha256sums=('68c75a03a06b935afa93d3331ca1c2d862c1d50c3e9df19d9a8d48970d766b55')
#write file and close editor
# now download the sources by running the build file
makepkg -o
# compile the project
makepkg -ef
# all should be good, now install the project
makepkg --install
# I like to use the 3 step makepkg method above to make sure each part succeeds.
# now when you start gkrellm and click on the about menu option, you should see
#  GKrellM 2.5.0