For many eduroam users very short-term action is required: In connection with the expiry of the root certificate “Deutsche Telekom Root CA 2” on July 10th, 2019, which has already been announced for some time, the certificate used to encrypt the WLAN eduroam login process will lose its validity on July 1st, 2019. All users concerned need to update their configuration to use the popular and widespread WLAN eduroam even after this date. Detailed instructions on how to set up eduroam for the various operating systems can be found on our website at https://gwdg.de/wlan. In most cases, the setup can be done by downloading and installing a small program, the so-called CAT tool, in just under five minutes per device.