diff --git a/CHANGELOG.md b/CHANGELOG.md
index bc719254..e56d1f6f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,7 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
-## Unreleased
+## [1.9.0] - 2021-05-09
 
 ### Added
 
diff --git a/Cargo.toml b/Cargo.toml
index 2d505c16..6ecc9a01 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,7 +11,7 @@ authors = [
     "Marcin Kaźmierczak",
 ]
 name = "serde_with"
-version = "1.8.1"
+version = "1.9.0"
 
 categories = ["encoding"]
 description = "Custom de/serialization functions for Rust's serde"
diff --git a/README.md b/README.md
index 3b8f330f..7a12e5d8 100644
--- a/README.md
+++ b/README.md
@@ -30,7 +30,7 @@ Add this to your `Cargo.toml`:
 
 ```toml
 [dependencies.serde_with]
-version = "1.8.1"
+version = "1.9.0"
 features = [ "..." ]
 ```
 
@@ -124,15 +124,15 @@ Foo {
 }
 ```
 
-[`DisplayFromStr`]: https://docs.rs/serde_with/1.8.1/serde_with/struct.DisplayFromStr.html
-[`with_prefix!`]: https://docs.rs/serde_with/1.8.1/serde_with/macro.with_prefix.html
-[display_fromstr]: https://docs.rs/serde_with/1.8.1/serde_with/rust/display_fromstr/index.html
-[feature flags]: https://docs.rs/serde_with/1.8.1/serde_with/guide/feature_flags/index.html
-[skip_serializing_none]: https://docs.rs/serde_with/1.8.1/serde_with/attr.skip_serializing_none.html
-[StringWithSeparator]: https://docs.rs/serde_with/1.8.1/serde_with/rust/struct.StringWithSeparator.html
-[user guide]: https://docs.rs/serde_with/1.8.1/serde_with/guide/index.html
+[`DisplayFromStr`]: https://docs.rs/serde_with/1.9.0/serde_with/struct.DisplayFromStr.html
+[`with_prefix!`]: https://docs.rs/serde_with/1.9.0/serde_with/macro.with_prefix.html
+[display_fromstr]: https://docs.rs/serde_with/1.9.0/serde_with/rust/display_fromstr/index.html
+[feature flags]: https://docs.rs/serde_with/1.9.0/serde_with/guide/feature_flags/index.html
+[skip_serializing_none]: https://docs.rs/serde_with/1.9.0/serde_with/attr.skip_serializing_none.html
+[StringWithSeparator]: https://docs.rs/serde_with/1.9.0/serde_with/rust/struct.StringWithSeparator.html
+[user guide]: https://docs.rs/serde_with/1.9.0/serde_with/guide/index.html
 [with-annotation]: https://serde.rs/field-attrs.html#with
-[as-annotation]: https://docs.rs/serde_with/1.8.1/serde_with/guide/serde_as/index.html
+[as-annotation]: https://docs.rs/serde_with/1.9.0/serde_with/guide/serde_as/index.html
 
 ## License
 
diff --git a/serde_with_macros/src/lib.rs b/serde_with_macros/src/lib.rs
index cd76bb23..b97437b6 100644
--- a/serde_with_macros/src/lib.rs
+++ b/serde_with_macros/src/lib.rs
@@ -479,8 +479,8 @@ fn field_has_attribute(field: &Field, namespace: &str, name: &str) -> bool {
 /// }
 /// ```
 ///
-/// [`serde_as`]: https://docs.rs/serde_with/1.8.1/serde_with/guide/index.html
-/// [re-exporting `serde_as`]: https://docs.rs/serde_with/1.8.1/serde_with/guide/serde_as/index.html#re-exporting-serde_as
+/// [`serde_as`]: https://docs.rs/serde_with/1.9.0/serde_with/guide/index.html
+/// [re-exporting `serde_as`]: https://docs.rs/serde_with/1.9.0/serde_with/guide/serde_as/index.html#re-exporting-serde_as
 #[proc_macro_attribute]
 pub fn serde_as(args: TokenStream, input: TokenStream) -> TokenStream {
     #[derive(FromMeta, Debug)]
@@ -783,7 +783,7 @@ fn replace_infer_type_with_type(to_replace: Type, replacement: &Type) -> Type {
 /// [`Display`]: std::fmt::Display
 /// [`FromStr`]: std::str::FromStr
 /// [cargo-toml-rename]: https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#renaming-dependencies-in-cargotoml
-/// [serde-as-crate]: https://docs.rs/serde_with/1.8.1/serde_with/guide/serde_as/index.html#re-exporting-serde_as
+/// [serde-as-crate]: https://docs.rs/serde_with/1.9.0/serde_with/guide/serde_as/index.html#re-exporting-serde_as
 /// [serde-crate]: https://serde.rs/container-attrs.html#crate
 #[proc_macro_derive(DeserializeFromStr, attributes(serde_with))]
 pub fn derive_deserialize_fromstr(item: TokenStream) -> TokenStream {
@@ -893,7 +893,7 @@ fn deserialize_fromstr(input: DeriveInput, serde_with_crate_path: Path) -> Token
 /// [`Display`]: std::fmt::Display
 /// [`FromStr`]: std::str::FromStr
 /// [cargo-toml-rename]: https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#renaming-dependencies-in-cargotoml
-/// [serde-as-crate]: https://docs.rs/serde_with/1.8.1/serde_with/guide/serde_as/index.html#re-exporting-serde_as
+/// [serde-as-crate]: https://docs.rs/serde_with/1.9.0/serde_with/guide/serde_as/index.html#re-exporting-serde_as
 /// [serde-crate]: https://serde.rs/container-attrs.html#crate
 #[proc_macro_derive(SerializeDisplay, attributes(serde_with))]
 pub fn derive_serialize_display(item: TokenStream) -> TokenStream {
diff --git a/src/lib.rs b/src/lib.rs
index 2cafb384..633de023 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -25,7 +25,7 @@
 #![doc(test(attr(warn(rust_2018_idioms))))]
 // Not needed for 2018 edition and conflicts with `rust_2018_idioms`
 #![doc(test(no_crate_inject))]
-#![doc(html_root_url = "https://docs.rs/serde_with/1.8.1")]
+#![doc(html_root_url = "https://docs.rs/serde_with/1.9.0")]
 // Necessary to silence the warning about clippy::unknown_clippy_lints on nightly
 #![allow(renamed_and_removed_lints)]
 // Rust 1.45: introduction of `strip_prefix` used by clippy::manual_strip
@@ -38,7 +38,7 @@
 //!
 //! ---
 //!
-//! This crate provides custom de/serialization helpers to use in combination with [serde's with-annotation][with-annotation] and with the improved [`serde_as`][user guide]-annotation.
+//! This crate provides custom de/serialization helpers to use in combination with [serde's with-annotation][with-annotation] and with the improved [`serde_as`][as-annotation]-annotation.
 //! Some common use cases are:
 //!
 //! * De/Serializing a type using the `Display` and `FromStr` traits, e.g., for `u8`, `url::Url`, or `mime::Mime`.
@@ -61,7 +61,7 @@
 //!
 //! ```toml
 //! [dependencies.serde_with]
-//! version = "1.8.1"
+//! version = "1.9.0"
 //! features = [ "..." ]
 //! ```
 //!
@@ -200,14 +200,15 @@
 //! # }
 //! ```
 //!
-//! [`DisplayFromStr`]: https://docs.rs/serde_with/1.8.1/serde_with/struct.DisplayFromStr.html
-//! [`with_prefix!`]: https://docs.rs/serde_with/1.8.1/serde_with/macro.with_prefix.html
-//! [display_fromstr]: https://docs.rs/serde_with/1.8.1/serde_with/rust/display_fromstr/index.html
-//! [feature flags]: https://docs.rs/serde_with/1.8.1/serde_with/guide/feature_flags/index.html
-//! [skip_serializing_none]: https://docs.rs/serde_with/1.8.1/serde_with/attr.skip_serializing_none.html
-//! [StringWithSeparator]: https://docs.rs/serde_with/1.8.1/serde_with/rust/struct.StringWithSeparator.html
-//! [user guide]: https://docs.rs/serde_with/1.8.1/serde_with/guide/index.html
+//! [`DisplayFromStr`]: https://docs.rs/serde_with/1.9.0/serde_with/struct.DisplayFromStr.html
+//! [`with_prefix!`]: https://docs.rs/serde_with/1.9.0/serde_with/macro.with_prefix.html
+//! [display_fromstr]: https://docs.rs/serde_with/1.9.0/serde_with/rust/display_fromstr/index.html
+//! [feature flags]: https://docs.rs/serde_with/1.9.0/serde_with/guide/feature_flags/index.html
+//! [skip_serializing_none]: https://docs.rs/serde_with/1.9.0/serde_with/attr.skip_serializing_none.html
+//! [StringWithSeparator]: https://docs.rs/serde_with/1.9.0/serde_with/rust/struct.StringWithSeparator.html
+//! [user guide]: https://docs.rs/serde_with/1.9.0/serde_with/guide/index.html
 //! [with-annotation]: https://serde.rs/field-attrs.html#with
+//! [as-annotation]: https://docs.rs/serde_with/1.9.0/serde_with/guide/serde_as/index.html
 
 #[doc(hidden)]
 pub extern crate serde;
@@ -343,7 +344,7 @@ impl Separator for CommaSeparator {
 /// # }
 /// ```
 ///
-/// [serde_as]: https://docs.rs/serde_with/1.8.1/serde_with/attr.serde_as.html
+/// [serde_as]: https://docs.rs/serde_with/1.9.0/serde_with/attr.serde_as.html
 #[derive(Copy, Clone, Debug, Default)]
 pub struct As<T: ?Sized>(PhantomData<T>);
 
@@ -809,7 +810,7 @@ pub struct BytesOrString;
 /// ```
 ///
 /// [`chrono::Duration`]: chrono_crate::Duration
-/// [feature flag]: https://docs.rs/serde_with/1.8.1/serde_with/guide/feature_flags/index.html
+/// [feature flag]: https://docs.rs/serde_with/1.9.0/serde_with/guide/feature_flags/index.html
 #[derive(Copy, Clone, Debug, Default)]
 pub struct DurationSeconds<
     FORMAT: formats::Format = u64,
@@ -935,7 +936,7 @@ pub struct DurationSeconds<
 /// ```
 ///
 /// [`chrono::Duration`]: chrono_crate::Duration
-/// [feature flag]: https://docs.rs/serde_with/1.8.1/serde_with/guide/feature_flags/index.html
+/// [feature flag]: https://docs.rs/serde_with/1.9.0/serde_with/guide/feature_flags/index.html
 #[derive(Copy, Clone, Debug, Default)]
 pub struct DurationSecondsWithFrac<
     FORMAT: formats::Format = f64,
@@ -1132,7 +1133,7 @@ pub struct DurationNanoSecondsWithFrac<
 ///
 /// [`SystemTime`]: std::time::SystemTime
 /// [DateTime]: chrono_crate::DateTime
-/// [feature flag]: https://docs.rs/serde_with/1.8.1/serde_with/guide/feature_flags/index.html
+/// [feature flag]: https://docs.rs/serde_with/1.9.0/serde_with/guide/feature_flags/index.html
 #[derive(Copy, Clone, Debug, Default)]
 pub struct TimestampSeconds<
     FORMAT: formats::Format = i64,
@@ -1261,7 +1262,7 @@ pub struct TimestampSeconds<
 ///
 /// [`SystemTime`]: std::time::SystemTime
 /// [DateTime]: chrono_crate::DateTime
-/// [feature flag]: https://docs.rs/serde_with/1.8.1/serde_with/guide/feature_flags/index.html
+/// [feature flag]: https://docs.rs/serde_with/1.9.0/serde_with/guide/feature_flags/index.html
 #[derive(Copy, Clone, Debug, Default)]
 pub struct TimestampSecondsWithFrac<
     FORMAT: formats::Format = f64,