Now that the company released the new version the package contains the version 2.0.X, but I don’t have licensing for it. Is there a way to also offer the older version (1.8.5) for everyone who is still using the old licensing model?
There is no automated way that I am aware of. You could see if the package is still in your cache and if so you can install it with sudo pacman -U /path/to/built/package. However, if it is built against old libraries it may not work.
For yay the cache is in ~/.cache/yay
You could also download the AUR files from commit e5d80a71a35f30de9c4ec2bfc259db6959e75a55 and then use makepkg to build the package