A new version of Raspbian is available from the Raspberry Pi Foundation: https://www.raspberrypi.org/downloads/raspbian/
The September, 2019 Raspbian as customized for the KSU workshops is available on Google drive. Beware: It is a 1.6 GB download from Google Drive; because of the size, you will get a warning that it’s too big for Google to scan for viruses. The easiest way to make one or a few SD cards from this image is to use balenaEtcher. Etcher is free, works on Windows, MacOS, and Linux, and will accept the .xz file directly; it is not necessary to extract the image from the archive. You will need 8 GB or larger SD cards for this image; 16 GB cards are better and cost about the same.
If you flash a card from this image, there will be an automatic reboot the first time it is started up because the image contains code to resize the file system on first boot in order to use the full capacity of the microSD card.