With the change from 2019 to 2020 Release the web documentation is changed to 2020. That makes it impossible wo work with XOJO because there is NO Online Help for Linux Systems and no Offline documentation for Linux Systems and no internal help system. Pressing help is leading to online help even if in IDE use offline help is setted. So it became impossible to work cause it is a blind fly. @Geoff_Perlman is this the way you want to press users in 2020? You byself said that they should use 2019 further. 2019 is with this decision under Linux not supported at all.
There could be the idea that it would be worth of your customers to copy the old page before changing it and to leave a button on the page like: for Web 2019 or for Web 1.0 look here. Would be the nice and professional way instead of killing all possibilities for customers.
Closing as this is a duplicate topic.
The offline documentation is supported on Linux. If it’s not working for you then you either are using an unsupported Linux distro or there’s a permissions issue. Please contact tech support for help on this.