diff --git a/tool/microkit/Cargo.toml b/tool/microkit/Cargo.toml
index 14d8aad0..de591b5d 100644
--- a/tool/microkit/Cargo.toml
+++ b/tool/microkit/Cargo.toml
@@ -8,6 +8,7 @@
 name = "microkit-tool"
 version = "1.4.0-dev"
 edition = "2021"
+rust-version = "1.79.0"
 
 [[bin]]
 name = "microkit"