diff --git a/Cargo.toml b/Cargo.toml
index b4f0d14a..d5be057b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -24,7 +24,7 @@ quantinuum-hugr = "0.2"
 portgraph = "0.11"
 pyo3 = "0.20"
 itertools = "0.12.0"
-tket-json-rs = "0.3.0"
+tket-json-rs = "0.4.0"
 tracing = "0.1.37"
 portmatching = "0.3.1"
 bytemuck = "1.14.0"