diff --git a/pyproject.toml b/pyproject.toml
index 16f8508..613c803 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -12,7 +12,7 @@ sinker = "sinker.__main__:main"
 [tool.poetry.dependencies]
 python = "^3.9"
 elasticsearch = "^8.6.1"
-environs = "^9.5.0"
+environs = ">=9.5,<11.0"
 psycopg = "^3.1.8"
 pytest-mock = "^3.10.0"