The announcement (and here) says
During the upgrade operation, you will be presented with a dialog box asking if you wish to disable
lighttpd
. Doing so is probably appropriate for most users – unless you are using it to host web pages other than Pi-hole’s, in which case you may choose to keep it enabled. Withlighttpd
disabled,pihole-FTL
will attempt to bind to ports 80 for HTTP and 443 for HTTPS. If there is any conflict on these ports, then it will revert to port 8080 for HTTP.
Presumably you had such a conflict. Please post a debug log URL.