This post answers, "How do I workaround the "Web Installer Client Obsolete" error?" You may get this error when trying to install a Xilinx/AMD tool via the webinstaller that's more than 3 years old. These steps were created and verified on July 8th, 2024.
Workaround Web Installer Client Obsolete
If you try to use a Web Installer older than three years (3 years quoted from link), you'll get an error message:

So, web install links won't work. However, you will need the filename from the link.
Don't click on the link; copy the link address

For Windows its:
For Linux its:
Now take the first part of the filename Xilinx_SDK_2015.4_1118_2 and construct this link:
https://www.xilinx.com/member/forms/download/xef.html?filename=Xilinx_Vivado_SDK_2015.4_1118_2.tar.gz
This file ^^^ has both the Windows and Linux installer and is 10.4 GB.
Or use the AMD link: