diff --git a/Cargo.lock b/Cargo.lock
index 7a4173e..bd7a4c8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 4
+version = 3
 
 [[package]]
 name = "aho-corasick"
diff --git a/Cargo.toml b/Cargo.toml
index b06a60a..c5c991a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,6 +12,7 @@ and fast access to the underlying strings.
 """
 categories = ["data-structures"]
 edition = "2021"
+rust-version = "1.65.0"
 
 [dependencies]
 hashbrown = { version = "0.16.0", default-features = false, features = ["default-hasher", "raw-entry"] }