SunRed [1] filed a request to merge lib32-libappindicator-gtk2 [2] into lib32-libappindicator [3]:

For easier maintaining this should be merged into the split package 'lib32-libappindicator'. After that, I am able to update the main package.

[1] https://aur.archlinux.org/account/SunRed/ [2] https://aur.archlinux.org/pkgbase/lib32-libappindicator-gtk2/ [3] https://aur.archlinux.org/pkgbase/lib32-libappindicator/