diff --git a/pyproject.toml b/pyproject.toml
index 3fe13c3..e764099 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -51,7 +51,7 @@ algosystem = "algosystem.interfaces.cli.main:cli"
 pytest = ">=9.0.3"
 pylint = "^3.1.0"
 black = ">=26.3.1"
-isort = "^5.13.2"
+isort = ">=5.13.2,<7.0.0"
 mypy = "^1.8.0"
 pytest-cov = "^5.0.0"
 backoff = "^1.2.1"