diff --git a/CHANGELOG.md b/CHANGELOG.md
index a0f0be6..9e31e1b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,10 +1,12 @@
 # Changelog
 
-## [0.3.2] - Unreleased
+## [0.4.0] - Unreleased
 ### Added
 - filesystem example in basic.rs
 - URL support in filesystem API on native targets when enabling the http feature
 
+    This breaks API compatibility as File::is_ready(&self) becomes File::is_ready(&mut self)
+
 ## [0.3.1] - 2023-01-13
 ### Fixed
 - fixed wasm target compilation
diff --git a/Cargo.toml b/Cargo.toml
index b8c448b..ffca19b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "uni-app"
-version = "0.3.2"
+version = "0.4.0"
 authors = [
     "Edwin Cheng <edwin0cheng@gmail.com>",
     "jice <jice.nospam@gmail.com>"
diff --git a/examples/Cargo.toml b/examples/Cargo.toml
index 189aa01..774c57f 100644
--- a/examples/Cargo.toml
+++ b/examples/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "uni-app-example"
-version = "0.3.2"
+version = "0.4.0"
 edition = "2021"
 license = "MIT"
 repository = "https://github.com/unrust/uni-app"
diff --git a/src/native_fs.rs b/src/native_fs.rs
index 8b46677..52a1c44 100644
--- a/src/native_fs.rs
+++ b/src/native_fs.rs
@@ -66,7 +66,7 @@ impl File {
     /// On web target, files are loaded asynchronously.
     /// You have to poll [`File::is_ready`] until it returns true.
     /// Only then you can call [`File::read_binary`] or [`File::read_text`].
-    pub fn is_ready(&self) -> bool {
+    pub fn is_ready(&mut self) -> bool {
         true
     }
 }
diff --git a/src/web_fs.rs b/src/web_fs.rs
index f79c3c4..106d51f 100644
--- a/src/web_fs.rs
+++ b/src/web_fs.rs
@@ -63,7 +63,7 @@ impl FileSystem {
 }
 
 impl File {
-    pub fn is_ready(&self) -> bool {
+    pub fn is_ready(&mut self) -> bool {
         let bs = self.buffer_state.borrow();
         match *bs {
             BufferState::Empty => false,