diff --git a/Cargo.toml b/Cargo.toml
index 777f74e..385dd52 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "lamport_sigs"
-version = "0.4.0"
+version = "0.4.1-pre"
 authors = ["Frederic Jacobs <github@fredericjacobs.com>"]
 description = "lamport_sigs is a Rust implementation of the Lamport one-time signature scheme."
 license = "BSD-3-Clause"