I have a Pi which I connect to two different WiFi routers according to the location. For simplicity, I want to use a fixed IP address for the Pi but the two routers have different IP addresses, requiring a different default router in the Pi IP configuration.
Under Wheezy this was quite easy to set up. In wpa_supplicant.conf I could associate an id with each network and use these ids in /etc/network/interfaces to specify different IP configurations, but I recently upgraded to the latest Stretch where this doesn't work, as the IP config is set up in /etc/dhcpcd.conf.
Can anyone please point me to an equivalent mechanism?