diff --git a/.github/workflows/python-package.yml b/.github/workflows/python-package.yml
index 6ee9d2b..e8aaca7 100644
--- a/.github/workflows/python-package.yml
+++ b/.github/workflows/python-package.yml
@@ -50,7 +50,7 @@ jobs:
   coincurve_versions:
     strategy:
       matrix:
-        coincurve-version: [15, 16, 17, 18, '19.0.1', 20]
+        coincurve-version: [15, 16, 17, 18, '19.0.1', 20, 21]
 
     runs-on: ubuntu-latest
     steps:
diff --git a/pyproject.toml b/pyproject.toml
index dcd6bc9..ea80fa7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ build-backend = "setuptools.build_meta"
 name = "bip32"
 version = "5.0.0"
 dependencies = [
-    "coincurve>=15.0,<21",
+    "coincurve>=15.0,<22",
 ]
 requires-python = ">=3.9"
 authors = [