diff --git a/Cargo.toml b/Cargo.toml
index 76ab9a3..b6cff98 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,7 +12,7 @@ readme = "README.md"
 cortex-m = "0.6.1"
 cortex-m-rt = "0.6.11"
 cortex-m-semihosting = "0.3.5"
-heapless = "0.4.2"
+heapless = "0.5.1"
 panic-semihosting = "0.5.3"
 
 [dependencies.cortex-m-rtfm]