diff --git a/pyproject.toml b/pyproject.toml
index 294adefe9..80bb5905a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -5,6 +5,6 @@ requires = ["setuptools",
             "cymem>=2.0.2,<2.1.0",
             "preshed>=2.0.1,<2.1.0",
             "murmurhash>=0.28.0,<1.1.0",
-            "thinc>=6.12.1,<6.13.0",
+            "thinc==7.0.0.dev6",
             ]
 build-backend = "setuptools.build_meta"