diff --git a/Cargo.lock b/Cargo.lock
index bf20ff4..3da10ff 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -910,7 +910,7 @@ checksum = "f497285884f3fcff424ffc933e56d7cbca511def0c9831a7f9b5f6153e3cc89b"
 
 [[package]]
 name = "retina"
-version = "0.3.9"
+version = "0.4.0-alpha.0"
 dependencies = [
  "anyhow",
  "base64",
diff --git a/Cargo.toml b/Cargo.toml
index ee533ad..b9659be 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "retina"
-version = "0.3.9"
+version = "0.4.0-alpha.0"
 authors = ["Scott Lamb <slamb@slamb.org>"]
 license = "MIT/Apache-2.0"
 edition = "2018"
diff --git a/fuzz/Cargo.lock b/fuzz/Cargo.lock
index 1b94b8c..fce22bb 100644
--- a/fuzz/Cargo.lock
+++ b/fuzz/Cargo.lock
@@ -530,7 +530,7 @@ checksum = "6c230d73fb8d8c1b9c0b3135c5142a8acee3a0558fb8db5cf1cb65f8d7862132"
 
 [[package]]
 name = "retina"
-version = "0.3.9"
+version = "0.4.0-alpha.0"
 dependencies = [
  "base64",
  "bitreader",