As of v4.0, Pi-hole ships with _FTL_DNS, our fork of dnsmasq, which should restore compatibility with Raspbian Jessie. We still recommend installing a newer OS as Jessie is EOL anyway.
By default, Raspbian Jessie only supports dnsmasq v2.72, which does not work with the log-queries=extra flag, which is required for Pi-hole v3.3+. You may see error messages such as:
dnsmasq: extraneous parameter at line 37 of /etc/dnsmasq.d/01-pihole.conf
failed!
There are two options if you can't or don't want to update past Jessie:
Stay on Raspbian Jessie and run Pi-hole v3.2.1
Upgrade dnsmasq manually to v2.76 (v2.73+)
For option one, if you already updated to Pi-hole v3.3 and realized it didn't work, you can downgrade your Pi-hole installation:
For option, two you can follow these instructions: