The legacy PCRE implementation (more recently referred to as PCRE1) is no longer being updated, with v8.45 (from June 2021) expected to be the final version.

Also, nginx has recently (nginx/1.21.5) changed to use PCRE2 by default, and this will cause problems if not using the --without-pcre2 flag when building (see owasp-modsecurity/ModSecurity-nginx#260, owasp-modsecurity/ModSecurity-nginx#261 ).