diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 39c90b7..ed54d2f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -52,7 +52,7 @@ jobs:
         os: [ubuntu-latest, windows-latest]
         # When updating this, the reminder to update the minimum supported
         # Rust version in Cargo.toml.
-        rust: ['1.48']
+        rust: ['1.63']
     steps:
       - uses: actions/checkout@v3
       - name: Install Rust
diff --git a/Cargo.toml b/Cargo.toml
index fd05bff..1da6bf1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,7 +6,7 @@ name = "async-process"
 version = "1.7.0"
 authors = ["Stjepan Glavina <stjepang@gmail.com>"]
 edition = "2018"
-rust-version = "1.48"
+rust-version = "1.63"
 description = "Async interface for working with processes"
 license = "Apache-2.0 OR MIT"
 repository = "https://github.com/smol-rs/async-process"
@@ -20,9 +20,6 @@ cfg-if = "1.0"
 event-listener = "2.4.0"
 futures-lite = "1.11.0"
 
-[build-dependencies]
-autocfg = "1"
-
 [target.'cfg(unix)'.dependencies]
 async-io = "1.8"
 rustix = { version = "0.37", default-features = false, features = ["std", "fs"] }
diff --git a/build.rs b/build.rs
deleted file mode 100644
index 6752846..0000000
--- a/build.rs
+++ /dev/null
@@ -1,19 +0,0 @@
-fn main() {
-    let cfg = match autocfg::AutoCfg::new() {
-        Ok(cfg) => cfg,
-        Err(e) => {
-            println!(
-                "cargo:warning=async-process: failed to detect compiler features: {}",
-                e
-            );
-            return;
-        }
-    };
-
-    if !cfg.probe_rustc_version(1, 62) {
-        autocfg::emit("async_process_no_windows_raw_arg");
-    }
-    if !cfg.probe_rustc_version(1, 63) {
-        autocfg::emit("async_process_no_io_safety");
-    }
-}
diff --git a/src/lib.rs b/src/lib.rs
index 0b7e59e..220b328 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -60,12 +60,10 @@ use std::thread;
 
 #[cfg(unix)]
 use async_io::Async;
-#[cfg(all(not(async_process_no_io_safety), unix))]
-use std::convert::{TryFrom, TryInto};
-#[cfg(all(not(async_process_no_io_safety), unix))]
-use std::os::unix::io::{AsFd, BorrowedFd, OwnedFd};
 #[cfg(unix)]
-use std::os::unix::io::{AsRawFd, RawFd};
+use std::convert::{TryFrom, TryInto};
+#[cfg(unix)]
+use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, OwnedFd, RawFd};
 
 #[cfg(windows)]
 use blocking::Unblock;
@@ -519,16 +517,14 @@ impl AsRawFd for ChildStdin {
     }
 }
 
-/// **Note:** This implementation is only available on Rust 1.63+.
-#[cfg(all(not(async_process_no_io_safety), unix))]
+#[cfg(unix)]
 impl AsFd for ChildStdin {
     fn as_fd(&self) -> BorrowedFd<'_> {
         self.0.as_fd()
     }
 }
 
-/// **Note:** This implementation is only available on Rust 1.63+.
-#[cfg(all(not(async_process_no_io_safety), unix))]
+#[cfg(unix)]
 impl TryFrom<ChildStdin> for OwnedFd {
     type Error = io::Error;
 
@@ -605,16 +601,14 @@ impl AsRawFd for ChildStdout {
     }
 }
 
-/// **Note:** This implementation is only available on Rust 1.63+.
-#[cfg(all(not(async_process_no_io_safety), unix))]
+#[cfg(unix)]
 impl AsFd for ChildStdout {
     fn as_fd(&self) -> BorrowedFd<'_> {
         self.0.as_fd()
     }
 }
 
-/// **Note:** This implementation is only available on Rust 1.63+.
-#[cfg(all(not(async_process_no_io_safety), unix))]
+#[cfg(unix)]
 impl TryFrom<ChildStdout> for OwnedFd {
     type Error = io::Error;
 
@@ -680,16 +674,14 @@ impl AsRawFd for ChildStderr {
     }
 }
 
-/// **Note:** This implementation is only available on Rust 1.63+.
-#[cfg(all(not(async_process_no_io_safety), unix))]
+#[cfg(unix)]
 impl AsFd for ChildStderr {
     fn as_fd(&self) -> BorrowedFd<'_> {
         self.0.as_fd()
     }
 }
 
-/// **Note:** This implementation is only available on Rust 1.63+.
-#[cfg(all(not(async_process_no_io_safety), unix))]
+#[cfg(unix)]
 impl TryFrom<ChildStderr> for OwnedFd {
     type Error = io::Error;
 
diff --git a/src/windows.rs b/src/windows.rs
index 453d3a5..020a290 100644
--- a/src/windows.rs
+++ b/src/windows.rs
@@ -1,6 +1,5 @@
 //! Windows-specific extensions.
 
-#[cfg(not(async_process_no_windows_raw_arg))]
 use std::ffi::OsStr;
 use std::os::windows::io::{AsRawHandle, RawHandle};
 use std::os::windows::process::CommandExt as _;
@@ -23,9 +22,6 @@ pub trait CommandExt: crate::sealed::Sealed {
     ///
     /// This is useful for passing arguments to `cmd.exe /c`, which doesn't follow
     /// `CommandLineToArgvW` escaping rules.
-    ///
-    /// **Note:** This method is only available on Rust 1.62+.
-    #[cfg(not(async_process_no_windows_raw_arg))]
     fn raw_arg<S: AsRef<OsStr>>(&mut self, text_to_append_as_is: S) -> &mut Command;
 }
 
@@ -36,7 +32,6 @@ impl CommandExt for Command {
         self
     }
 
-    #[cfg(not(async_process_no_windows_raw_arg))]
     fn raw_arg<S: AsRef<OsStr>>(&mut self, text_to_append_as_is: S) -> &mut Command {
         self.inner.raw_arg(text_to_append_as_is);
         self