A reminder - We announced an end to formal support of suricata 4.x rulesets for etpro and ET Open back in August with an effective date of September 2024. We extended that throughout 2024, but as of January 6, 2025 we have ceased releasing new and updated rules to that set.
Download attempts to those rules (https://rules.emergingthreatspro.com/open/old/suricata-4.0/…) will serve the last-known-good version, dated January 8, 2025.