diff --git a/Cargo.toml b/Cargo.toml
index e02fb6800..e052ed745 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -40,7 +40,7 @@ futures = "0.3"
 # Conversion
 frunk = { version = "0.3.0", optional = true }
 frunk_derives = { version = "0.3.0", optional = true }
-frunk_core = { version = "0.3.0", optional = true }
+frunk_core = { version = "0.4.0", optional = true }
 frunk-enum-derive = { version = "0.2.1", optional = true }
 frunk-enum-core = { version = "0.2.1", optional = true }