diff --git a/rtic_v1/stm32l4_heartbeat/Cargo.toml b/rtic_v1/stm32l4_heartbeat/Cargo.toml
index 282f3e3..95e1f7f 100644
--- a/rtic_v1/stm32l4_heartbeat/Cargo.toml
+++ b/rtic_v1/stm32l4_heartbeat/Cargo.toml
@@ -19,7 +19,7 @@ stm32l4xx-hal = { version = "0.7.1", features = ["rt", "stm32l412"] }
 heapless = "0.7.10"
 systick-monotonic = "1.0.0"
 panic-rtt-target = { version = "0.1.2", features = ["cortex-m"] }
-rtt-target = { version = "0.3.1", features = ["cortex-m"] }
+rtt-target = { version = "0.4.0", features = ["cortex-m"] }
 
 # this lets you use `cargo fix`!
 [[bin]]