diff --git a/embedded-hal-async/build.rs b/embedded-hal-async/build.rs
deleted file mode 100644
index 78bd27ec7..000000000
--- a/embedded-hal-async/build.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-use std::env;
-use std::ffi::OsString;
-use std::process::Command;
-
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-
-    let rustc = env::var_os("RUSTC").unwrap_or_else(|| OsString::from("rustc"));
-
-    let output = Command::new(rustc)
-        .arg("--version")
-        .output()
-        .expect("failed to run `rustc --version`");
-
-    if String::from_utf8_lossy(&output.stdout).contains("nightly") {
-        println!("cargo:rustc-cfg=nightly");
-    }
-}
diff --git a/embedded-hal-async/src/lib.rs b/embedded-hal-async/src/lib.rs
index 44901deca..cbd74f5d4 100644
--- a/embedded-hal-async/src/lib.rs
+++ b/embedded-hal-async/src/lib.rs
@@ -1,12 +1,6 @@
 #![doc = include_str!("../README.md")]
 #![warn(missing_docs)]
 #![no_std]
-// disable warning for already-stabilized features.
-// Needed to pass CI, because we deny warnings.
-// We don't immediately remove them to not immediately break older nightlies.
-// When all features are stable, we'll remove them.
-#![cfg_attr(nightly, allow(stable_features, unknown_lints))]
-#![cfg_attr(nightly, feature(async_fn_in_trait, impl_trait_projections))]
 #![allow(async_fn_in_trait)]
 
 pub mod delay;
diff --git a/embedded-hal-bus/build.rs b/embedded-hal-bus/build.rs
deleted file mode 100644
index 78bd27ec7..000000000
--- a/embedded-hal-bus/build.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-use std::env;
-use std::ffi::OsString;
-use std::process::Command;
-
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-
-    let rustc = env::var_os("RUSTC").unwrap_or_else(|| OsString::from("rustc"));
-
-    let output = Command::new(rustc)
-        .arg("--version")
-        .output()
-        .expect("failed to run `rustc --version`");
-
-    if String::from_utf8_lossy(&output.stdout).contains("nightly") {
-        println!("cargo:rustc-cfg=nightly");
-    }
-}
diff --git a/embedded-hal-bus/src/lib.rs b/embedded-hal-bus/src/lib.rs
index 396043a31..dfeca16e1 100644
--- a/embedded-hal-bus/src/lib.rs
+++ b/embedded-hal-bus/src/lib.rs
@@ -2,15 +2,6 @@
 #![warn(missing_docs)]
 #![cfg_attr(not(feature = "std"), no_std)]
 #![cfg_attr(docsrs, feature(doc_cfg))]
-// disable warning for already-stabilized features.
-// Needed to pass CI, because we deny warnings.
-// We don't immediately remove them to not immediately break older nightlies.
-// When all features are stable, we'll remove them.
-#![cfg_attr(all(feature = "async", nightly), allow(stable_features))]
-#![cfg_attr(
-    all(feature = "async", nightly),
-    feature(async_fn_in_trait, impl_trait_projections)
-)]
 
 // needed to prevent defmt macros from breaking, since they emit code that does `defmt::blahblah`.
 #[cfg(feature = "defmt-03")]
diff --git a/embedded-io-adapters/build.rs b/embedded-io-adapters/build.rs
deleted file mode 100644
index 78bd27ec7..000000000
--- a/embedded-io-adapters/build.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-use std::env;
-use std::ffi::OsString;
-use std::process::Command;
-
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-
-    let rustc = env::var_os("RUSTC").unwrap_or_else(|| OsString::from("rustc"));
-
-    let output = Command::new(rustc)
-        .arg("--version")
-        .output()
-        .expect("failed to run `rustc --version`");
-
-    if String::from_utf8_lossy(&output.stdout).contains("nightly") {
-        println!("cargo:rustc-cfg=nightly");
-    }
-}
diff --git a/embedded-io-adapters/src/lib.rs b/embedded-io-adapters/src/lib.rs
index f9d0f1a5c..9d6628836 100644
--- a/embedded-io-adapters/src/lib.rs
+++ b/embedded-io-adapters/src/lib.rs
@@ -2,18 +2,6 @@
 #![cfg_attr(docsrs, feature(doc_cfg))]
 #![warn(missing_docs)]
 #![doc = include_str!("../README.md")]
-// disable warning for already-stabilized features.
-// Needed to pass CI, because we deny warnings.
-// We don't immediately remove them to not immediately break older nightlies.
-// When all features are stable, we'll remove them.
-#![cfg_attr(
-    all(any(feature = "tokio-1", feature = "futures-03"), nightly),
-    allow(stable_features)
-)]
-#![cfg_attr(
-    all(any(feature = "tokio-1", feature = "futures-03"), nightly),
-    feature(async_fn_in_trait, impl_trait_projections)
-)]
 
 #[cfg(feature = "std")]
 #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
diff --git a/embedded-io-async/build.rs b/embedded-io-async/build.rs
deleted file mode 100644
index 78bd27ec7..000000000
--- a/embedded-io-async/build.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-use std::env;
-use std::ffi::OsString;
-use std::process::Command;
-
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-
-    let rustc = env::var_os("RUSTC").unwrap_or_else(|| OsString::from("rustc"));
-
-    let output = Command::new(rustc)
-        .arg("--version")
-        .output()
-        .expect("failed to run `rustc --version`");
-
-    if String::from_utf8_lossy(&output.stdout).contains("nightly") {
-        println!("cargo:rustc-cfg=nightly");
-    }
-}
diff --git a/embedded-io-async/src/lib.rs b/embedded-io-async/src/lib.rs
index 1171d42a0..7c0ac2d55 100644
--- a/embedded-io-async/src/lib.rs
+++ b/embedded-io-async/src/lib.rs
@@ -2,12 +2,6 @@
 #![cfg_attr(docsrs, feature(doc_cfg))]
 #![warn(missing_docs)]
 #![doc = include_str!("../README.md")]
-// disable warning for already-stabilized features.
-// Needed to pass CI, because we deny warnings.
-// We don't immediately remove them to not immediately break older nightlies.
-// When all features are stable, we'll remove them.
-#![cfg_attr(nightly, allow(stable_features, unknown_lints))]
-#![cfg_attr(nightly, feature(async_fn_in_trait, impl_trait_projections))]
 #![allow(async_fn_in_trait)]
 
 #[cfg(feature = "alloc")]