diff --git a/Cargo.toml b/Cargo.toml
index 03fa370..e4e3484 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -23,7 +23,7 @@ tracing = { version = "0.1.16", default-features = false, features = ["std"], op
 
 # builder
 hyperx = { version = "1", optional = true, features = ["headers"] }
-mime = { version = "0.3", optional = true }
+mime = { version = "0.3.4", optional = true }
 uuid = { version = "0.8", features = ["v4"] }
 rand = { version = "0.8", optional = true }
 quoted_printable = { version = "0.4", optional = true }