diff --git a/pyproject.toml b/pyproject.toml
index 7c6374e..e6f1847 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -36,7 +36,7 @@ packages = [
 [tool.poetry.dependencies]
 python = "^3.7"
 biotite = ">= 0.32"
-numpy = "^1.15"
+numpy = ">=1.15"
 
 [tool.poetry.dev-dependencies]
 pytest = "^5.2"