diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs
index cba1ce40f75d5..10f26ab6c0082 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_convert)]
diff --git a/library/alloctests/lib.rs b/library/alloctests/lib.rs
index 0201c8752210c..fcecf988c71b0 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 8c3ce156f3c1d..c8e41901beeec 100644
--- a/library/alloctests/tests/lib.rs
+++ b/library/alloctests/tests/lib.rs
@@ -3,7 +3,6 @@
 #![feature(iter_array_chunks)]
 #![feature(assert_matches)]
 #![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 76f54db287079..a4d6d292c0453 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 a246c80614063..601850c3e9f0d 100644
--- a/library/coretests/tests/lib.rs
+++ b/library/coretests/tests/lib.rs
@@ -14,7 +14,6 @@
 #![feature(bstr)]
 #![feature(cfg_target_has_reliable_f16_f128)]
 #![feature(char_internals)]
-#![feature(char_max_len)]
 #![feature(clone_to_uninit)]
 #![feature(const_cmp)]
 #![feature(const_convert)]
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index 5725816c6003c..235d22f5ffa7e 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -279,7 +279,6 @@
 #![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)]