diff --git a/openmetrics-spec-tests/check_openmetrics_spec_requirements.txt b/openmetrics-spec-tests/check_openmetrics_spec_requirements.txt
index ecc186d6d..bb3e776c2 100644
--- a/openmetrics-spec-tests/check_openmetrics_spec_requirements.txt
+++ b/openmetrics-spec-tests/check_openmetrics_spec_requirements.txt
@@ -1 +1 @@
--e git+https://github.com/declaresub/abnf.git@6dc48bc44219e523c2a21ec7a09c104d991b09d0#egg=abnf # 2.3.1
+-e git+https://github.com/declaresub/abnf.git@23f0f21d4c58fbc10dbb6ff3bfee7d8111b373cc#egg=abnf # 2.4.1