diff --git a/Cargo.toml b/Cargo.toml
index f0a8d3f..50352aa 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "watt"
-version = "0.3.0"
+version = "0.4.0"
 authors = ["David Tolnay <dtolnay@gmail.com>"]
 license = "MIT OR Apache-2.0"
 description = "Runtime for executing Rust procedural macros compiled as WebAssembly."
diff --git a/README.md b/README.md
index 5afee7a..4780fcd 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@ Watt is a runtime for executing Rust procedural macros compiled as WebAssembly.
 
 ```toml
 [dependencies]
-watt = "0.3"
+watt = "0.4"
 ```
 
 *Compiler support: requires rustc 1.35+*
@@ -113,7 +113,7 @@ a new Cargo.toml, put:
 proc-macro = true
 
 [dependencies]
-watt = "0.3"
+watt = "0.4"
 ```
 
 And in its src/lib.rs, define real proc macros corresponding to each of the ones
diff --git a/demo/wa/Cargo.toml b/demo/wa/Cargo.toml
index 7cd22da..49b4aba 100644
--- a/demo/wa/Cargo.toml
+++ b/demo/wa/Cargo.toml
@@ -9,4 +9,4 @@ publish = false
 proc-macro = true
 
 [dependencies]
-watt = "0.3"
+watt = "0.4"
diff --git a/proc-macro/src/ffi.rs b/proc-macro/src/ffi.rs
index 8677818..a37f9d9 100644
--- a/proc-macro/src/ffi.rs
+++ b/proc-macro/src/ffi.rs
@@ -4,7 +4,7 @@ use std::marker::PhantomData;
 use std::panic::{self, PanicInfo};
 use std::sync::Once;
 
-#[link(wasm_import_module = "watt-0.3")]
+#[link(wasm_import_module = "watt-0.4")]
 extern "C" {
     fn token_stream_serialize(stream: u32) -> handle::Bytes;
     fn token_stream_deserialize(ptr: *const u8, len: usize) -> u32;
diff --git a/src/interpret.rs b/src/interpret.rs
index fe52b14..eec16c1 100644
--- a/src/interpret.rs
+++ b/src/interpret.rs
@@ -119,7 +119,7 @@ fn extern_vals(module: &Module, store: &mut Store) -> Vec<ExternVal> {
 
 fn mk_host_func(import: Import, store: &mut Store) -> ExternVal {
     let (module, name, ref sig) = import;
-    assert_eq!(module, "watt-0.3", "Wasm import from unknown module");
+    assert_eq!(module, "watt-0.4", "Wasm import from unknown module");
     let func = match sig {
         Extern::Func(func) => func,
         Extern::Table(_) | Extern::Memory(_) | Extern::Global(_) => {
diff --git a/src/jit.rs b/src/jit.rs
index f45fc2f..fa14059 100644
--- a/src/jit.rs
+++ b/src/jit.rs
@@ -136,7 +136,7 @@ fn mk_host_func(import: &ImportType, store: &Store) -> Func {
     // TODO: assert `import` is a function import
     assert_eq!(
         import.module(),
-        "watt-0.3",
+        "watt-0.4",
         "Wasm import from unknown module"
     );
     import::host_func(import.name(), store)
diff --git a/src/lib.rs b/src/lib.rs
index 4c2587a..e06bcbb 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -112,7 +112,7 @@
 //! proc-macro = true
 //!
 //! [dependencies]
-//! watt = "0.3"
+//! watt = "0.4"
 //! ```
 //!
 //! And in its src/lib.rs, define real proc macros corresponding to each of the