diff --git a/requirements.txt b/requirements.txt
index 41a05df941..29a4ac0621 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,7 +5,7 @@ brotlipy==0.7.0; platform_python_implementation == "PyPy"
 unicodedata2==13.0.0.post2; python_version < '3.9' and platform_python_implementation != "PyPy"
 scipy==1.7.1; platform_python_implementation != "PyPy"
 munkres==1.1.4; platform_python_implementation == "PyPy"
-zopfli==0.1.6
+zopfli==0.1.8
 fs==2.4.11
 skia-pathops==0.5.1.post1; platform_python_implementation != "PyPy"
 # this is only required to run Tests/cu2qu/{ufo,cli}_test.py