diff --git a/Cargo.toml b/Cargo.toml
index ca6625c..f431f26 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,7 @@ license = "MPL-2.0"
 homepage = "https://github.com/badboy/mdbook-toc"
 repository = "https://github.com/badboy/mdbook-toc"
 edition = "2018"
+rust-version = "1.58"
 
 [dependencies]
 mdbook = "0.4.10"