diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs
index 711092ae8eb25..b39f7ed30f1b3 100644
--- a/library/alloc/src/lib.rs
+++ b/library/alloc/src/lib.rs
@@ -104,7 +104,6 @@
 #![feature(bstr_internals)]
 #![feature(cast_maybe_uninit)]
 #![feature(char_internals)]
-#![feature(char_max_len)]
 #![feature(clone_to_uninit)]
 #![feature(coerce_unsized)]
 #![feature(const_default)]
diff --git a/library/alloctests/lib.rs b/library/alloctests/lib.rs
index 97de7d6a701ca..8b5f1190b3a74 100644
--- a/library/alloctests/lib.rs
+++ b/library/alloctests/lib.rs
@@ -19,7 +19,6 @@
 #![feature(array_into_iter_constructors)]
 #![feature(assert_matches)]
 #![feature(char_internals)]
-#![feature(char_max_len)]
 #![feature(core_intrinsics)]
 #![feature(exact_size_is_empty)]
 #![feature(extend_one)]
diff --git a/library/alloctests/tests/lib.rs b/library/alloctests/tests/lib.rs
index 447af240a4b9d..339325238b274 100644
--- a/library/alloctests/tests/lib.rs
+++ b/library/alloctests/tests/lib.rs
@@ -4,7 +4,6 @@
 #![feature(assert_matches)]
 #![feature(btree_extract_if)]
 #![feature(wtf8_internals)]
-#![feature(char_max_len)]
 #![feature(cow_is_borrowed)]
 #![feature(core_intrinsics)]
 #![feature(downcast_unchecked)]
diff --git a/library/core/src/char/methods.rs b/library/core/src/char/methods.rs
index 985e669c92d79..c2ae4edcee50a 100644
--- a/library/core/src/char/methods.rs
+++ b/library/core/src/char/methods.rs
@@ -74,12 +74,12 @@ impl char {
 
     /// The maximum number of bytes required to [encode](char::encode_utf8) a `char` to
     /// UTF-8 encoding.
-    #[unstable(feature = "char_max_len", issue = "121714")]
+    #[stable(feature = "char_max_len", since = "CURRENT_RUSTC_VERSION")]
     pub const MAX_LEN_UTF8: usize = 4;
 
     /// The maximum number of two-byte units required to [encode](char::encode_utf16) a `char`
     /// to UTF-16 encoding.
-    #[unstable(feature = "char_max_len", issue = "121714")]
+    #[stable(feature = "char_max_len", since = "CURRENT_RUSTC_VERSION")]
     pub const MAX_LEN_UTF16: usize = 2;
 
     /// `U+FFFD REPLACEMENT CHARACTER` (�) is used in Unicode to represent a
diff --git a/library/core/src/char/mod.rs b/library/core/src/char/mod.rs
index 82a3f6f916be3..694424a5e0a58 100644
--- a/library/core/src/char/mod.rs
+++ b/library/core/src/char/mod.rs
@@ -97,12 +97,12 @@ pub const MAX: char = char::MAX;
 
 /// The maximum number of bytes required to [encode](char::encode_utf8) a `char` to
 /// UTF-8 encoding.
-#[unstable(feature = "char_max_len", issue = "121714")]
+#[stable(feature = "char_max_len", since = "CURRENT_RUSTC_VERSION")]
 pub const MAX_LEN_UTF8: usize = char::MAX_LEN_UTF8;
 
 /// The maximum number of two-byte units required to [encode](char::encode_utf16) a `char`
 /// to UTF-16 encoding.
-#[unstable(feature = "char_max_len", issue = "121714")]
+#[stable(feature = "char_max_len", since = "CURRENT_RUSTC_VERSION")]
 pub const MAX_LEN_UTF16: usize = char::MAX_LEN_UTF16;
 
 /// `U+FFFD REPLACEMENT CHARACTER` (�) is used in Unicode to represent a
diff --git a/library/coretests/tests/lib.rs b/library/coretests/tests/lib.rs
index 4415b61481708..6c74fefd5e654 100644
--- a/library/coretests/tests/lib.rs
+++ b/library/coretests/tests/lib.rs
@@ -13,7 +13,6 @@
 #![feature(bool_to_result)]
 #![feature(bstr)]
 #![feature(cfg_target_has_reliable_f16_f128)]
-#![feature(char_max_len)]
 #![feature(clone_to_uninit)]
 #![feature(const_deref)]
 #![feature(const_destruct)]
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index 30a1b10881784..b9198bd84d7ad 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -280,7 +280,6 @@
 #![feature(cfg_sanitizer_cfi)]
 #![feature(cfg_target_thread_local)]
 #![feature(cfi_encoding)]
-#![feature(char_max_len)]
 #![feature(const_trait_impl)]
 #![feature(core_float_math)]
 #![feature(decl_macro)]