diff --git a/Cargo.toml b/Cargo.toml
index a3db68c..29b3ffe 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,7 +13,7 @@ num-bigint = ">=0.4.3,<0.5"
 pyo3 = { version = ">=0.16.5,<0.17", features = ["extension-module", "num-bigint"] }
 pyo3-file = ">=0.5.0,<0.6"
 thiserror = ">=1.0.37,<2"
-utf8-chars = ">=2.0.2,<3"
+utf8-chars = ">=2.0.2, <4"
 
 [build-dependencies]
 pyo3-build-config = { version = "= 0.16.6", features = ["resolve-config"] }