diff --git a/Cargo.toml b/Cargo.toml
index 2274b84..9c5b68d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -176,3 +176,6 @@ used_underscore_items = "warn"
 verbose_bit_mask = "warn"
 wildcard_imports = "warn"
 zero_sized_map_values = "warn"
+
+[lints.rust]
+unexpected_cfgs = { level = "deny", check-cfg = ['cfg(rust_version, values(">= 1.81.0"))'] }
diff --git a/nightly-version b/nightly-version
index 952e0e5..d9c75e4 100644
--- a/nightly-version
+++ b/nightly-version
@@ -1 +1 @@
-nightly-2025-02-14
+nightly-2025-10-03
diff --git a/src/error.rs b/src/error.rs
index ab28fbe..b5f2c6e 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -63,7 +63,6 @@ macro_rules! write_err {
         }
     }
 }
-pub(crate) use write_err;
 
 /// Error returned when hex decoding a hex string with variable length.
 ///
diff --git a/src/lib.rs b/src/lib.rs
index 77f6256..716dcf9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -69,7 +69,6 @@
 #![no_std]
 // Experimental features we need.
 #![cfg_attr(docsrs, feature(doc_cfg))]
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
 // Coding conventions
 #![warn(missing_docs)]