diff --git a/Project.toml b/Project.toml
index cd71643..9f9b280 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "IonSim"
 uuid = "511e77fe-ab93-41f7-8f07-8f89809c6435"
 authors = ["Joseph Broz <jbroz@berkeley.edu>"]
-version = "0.3.3"
+version = "0.4.0"
 
 [deps]
 FunctionWrappers = "069b7b12-0de2-55c6-9aab-29f3d0a68a2e"