diff --git a/CHANGELOG.md b/CHANGELOG.md
index 72782046..aace7bb0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,10 @@ versions.
 
 ### Added
 
+- Resource types can now be registered implicitly via a `#[derive(Resource)]`
+  instead of explicit registration in a `load` function using
+  `rustler::resource!` (#617)
+
 ### Fixed
 
 ### Changed
diff --git a/UPGRADE.md b/UPGRADE.md
index d48083a9..1b6595df 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -7,6 +7,12 @@ This document is intended to simplify upgrading to newer versions by extending t
 1. NIF implementations are now discovered automatically, the respective argument
    in the `rustler::init!` macro should be removed. If a NIF implementation
    should not be exported, it must be disabled with a `#[cfg]` marker.
+2. The functionality related to the `derive` feature is now unconditionally
+   active. The feature flag is kept for compatibility for now but will be
+   removed in the future.
+3. To register a type as a resource, the new `#[derive(Resource)]` can be used
+   now. It is implicitly registered and does not require (or work in) the old
+   explicit registration with `rustler::resource!` a custom `load` function.
 
 ## 0.32 -> 0.33
 
diff --git a/rustler/Cargo.toml b/rustler/Cargo.toml
index 4401f23a..333cee89 100644
--- a/rustler/Cargo.toml
+++ b/rustler/Cargo.toml
@@ -11,8 +11,8 @@ rust-version = "1.70"
 
 [features]
 big_integer = ["dep:num-bigint"]
-default = ["derive", "nif_version_2_15"]
-derive = ["rustler_codegen"]
+default = ["nif_version_2_15"]
+derive = []
 alternative_nif_init_name = []
 allocator = []
 nif_version_2_14 = ["rustler_sys/nif_version_2_14"]
@@ -23,7 +23,7 @@ serde = ["dep:serde"]
 
 [dependencies]
 inventory = "0.3"
-rustler_codegen = { path = "../rustler_codegen", version = "0.33.0", optional = true}
+rustler_codegen = { path = "../rustler_codegen", version = "0.33.0" }
 rustler_sys = { path = "../rustler_sys", version = "~2.4.1" }
 num-bigint = { version = "0.4", optional = true }
 serde = { version = "1", optional = true }
diff --git a/rustler/src/lib.rs b/rustler/src/lib.rs
index 8166211f..ba3ec239 100644
--- a/rustler/src/lib.rs
+++ b/rustler/src/lib.rs
@@ -71,7 +71,6 @@ pub use nif::Nif;
 
 pub type NifResult<T> = Result<T, Error>;
 
-#[cfg(feature = "derive")]
 pub use rustler_codegen::{
     init, nif, NifException, NifMap, NifRecord, NifStruct, NifTaggedEnum, NifTuple, NifUnitEnum,
     NifUntaggedEnum, Resource,