diff --git a/pyproject.toml b/pyproject.toml
index 2537446..2bdb990 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,8 +23,8 @@
   ]
   dependencies = [
     "cosmology.api >= 0.1.0",
-    "cython",
-    "classy<3.0",
+    "cython>=3",
+    "classy>=3",
     "typing_extensions>=3.7.4.2",
     "scipy>1.5",
   ]