@dibdot, the old utility that worked on 4.0.6-1 was uclent-fetch, here is what I get after /etc/init.d/adblock restart with "Enable verbose debug logging in case of any processing errors" enabled
Sun Aug 23 15:54:02 2020 user.debug adblock-4.0.6[8864]: f_uci ::: config: dhcp, change:
Sun Aug 23 15:54:02 2020 user.debug adblock-4.0.6[8864]: f_uci ::: config: firewall, change:
Sun Aug 23 15:54:02 2020 user.debug adblock-4.0.6[8864]: f_temp ::: tmp_base: /mnt/sda1/adblock, tmp_dir: /mnt/sda1/adblock/tmp.HEfIFC, cores: 2, sort_options: --temporary-directory=/mnt/sda1/adblock/tmp.HEfIFC --compress-program=gzip --batch-size=32 --parallel=2, pid_file: /var/run/adblock.pid
Sun Aug 23 15:54:02 2020 user.debug adblock-4.0.6[8864]: f_main ::: memory: 478/342/342, max_queue: 16, safe_search: 0, force_dns: 0, awk: /usr/bin/awk
Sun Aug 23 15:54:02 2020 user.debug adblock-4.0.6[8864]: f_list ::: name: blacklist, mode: blacklist, cnt: 0, in_rc: 0, out_rc: 0
Sun Aug 23 15:54:03 2020 user.debug adblock-4.0.6[8864]: f_list ::: name: whitelist, mode: whitelist, cnt: 0, in_rc: 0, out_rc: 0
Sun Aug 23 15:54:04 2020 user.info adblock-4.0.6[8864]: preparation of 'disconnect' failed, rc: 2
Sun Aug 23 15:54:04 2020 user.debug adblock-4.0.6[8864]: f_list ::: name: disconnect, mode: restore, cnt: 0, in_rc: 2, out_rc: 4
Sun Aug 23 15:54:05 2020 user.info adblock-4.0.6[8864]: preparation of 'yoyo' failed, rc: 2
Sun Aug 23 15:54:05 2020 user.debug adblock-4.0.6[8864]: f_list ::: name: yoyo, mode: restore, cnt: 0, in_rc: 2, out_rc: 4
Sun Aug 23 15:54:05 2020 user.info adblock-4.0.6[8864]: preparation of 'adaway' failed, rc: 2
Sun Aug 23 15:54:05 2020 user.debug adblock-4.0.6[8864]: f_list ::: name: adaway, mode: restore, cnt: 0, in_rc: 2, out_rc: 4
Sun Aug 23 15:54:07 2020 user.info adblock-4.0.6[8864]: preparation of 'adguard' failed, rc: 2
Sun Aug 23 15:54:07 2020 user.debug adblock-4.0.6[8864]: f_list ::: name: adguard, mode: restore, cnt: 0, in_rc: 2, out_rc: 4
Sun Aug 23 15:54:09 2020 user.info adblock-4.0.6[8864]: archive preparation of 'shallalist' failed, categories: adv, entries: BL/adv/domains, rc: 2
Sun Aug 23 15:54:09 2020 user.debug adblock-4.0.6[8864]: f_list ::: name: shallalist, mode: restore, cnt: 0, in_rc: 2, out_rc: 4
Sun Aug 23 15:54:09 2020 user.debug adblock-4.0.6[8864]: f_list ::: name: -, mode: merge, cnt: 0, in_rc: 4, out_rc: 2
Sun Aug 23 15:54:16 2020 user.debug adblock-4.0.6[8864]: f_dnsup ::: lookup_util: /usr/bin/nslookup, lookup_domain: example.com, restart_rc: 0, dns_timeout: 20, dns_cnt: 0, in_rc: 0, out_rc: 0
Sun Aug 23 15:54:16 2020 user.debug adblock-4.0.6[8864]: f_jsnup ::: status: enabled, cnt: 0, mail: 0, mail_service: /etc/adblock/adblock.mail, mail_cnt: 0, mail_pid: -