diff --git a/pyproject.toml b/pyproject.toml
index 44ac8eb89..b3c6163c2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -28,7 +28,7 @@ classifiers = [
 ]
 keywords = ["email"]
 license = {file = "LICENSE"}
-dependencies = [ 
+dependencies = [
 	"django>4.0,<5.0",
 	"django-ckeditor==6.7.1",
 	"django-phonenumber-field[phonenumbers]==8.0.0",
@@ -97,7 +97,7 @@ test = [
 	"testfixtures==8.3.0",
 	"tox",
 ]
-ldap = ["django-auth-ldap>=1.3.0"]
+ldap = ["django-auth-ldap<5.0.0"]
 
 [project.scripts]
 modoboa-cli = "modoboa:modoboa_admin"