I have to connect my raspberry pi3+ to an WEP "secured" WiFi. I searched the netplan.io website but couldn't find an configuration example fitting my use case. Is netplan even supporting WEP configurations? Thanks!
The syntax is the same as for connecting to a WPA personal network: https://netplan.io/examples#connecting-to-a-wpa-personal-wireless-network
This isn't documented separately because WEP itself is deprecated and insecure.