We have been using SMAX in the documentation URLs since 2019.02 (https://docs.microfocus.com/itom/SMAX:<version number>/xxxxx), and redirects are set for previous versions.
However, if you have any trouble opening SMAX 2018.08 docs, please check if the URL includes "Service_Management_Automation_-_X" rather than "SMAX". Also don't forget to update the bookmark if you have any doc links bookmarked. The correct address is https://docs.microfocus.com/itom/SMAX:2018.08/Home.
For any doc issues, feel free to drop an email to email@example.com.