diff --git a/Cargo.toml b/Cargo.toml
index 16b99de07e3..cd4d6d0f7a3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,7 +22,7 @@ inventory = { version = "0.1.4", optional = true }
 libc = "0.2.62"
 parking_lot = "0.11.0"
 num-bigint = { version = "0.3", optional = true }
-num-complex = { version = "0.3", optional = true }
+num-complex = { version = "0.4", optional = true }
 paste = { version = "1.0.3", optional = true }
 pyo3cls = { path = "pyo3cls", version = "=0.12.4", optional = true }
 unindent = { version = "0.1.4", optional = true }