diff --git a/src/liballoc/string.rs b/src/liballoc/string.rs
index 61a207fc5b35c..5f684361fdc23 100644
--- a/src/liballoc/string.rs
+++ b/src/liballoc/string.rs
@@ -2239,7 +2239,7 @@ impl<'a> From<String> for Cow<'a, str> {
     }
 }
 
-#[stable(feature = "cow_from_string_ref", since = "1.27.0")]
+#[stable(feature = "cow_from_string_ref", since = "1.28.0")]
 impl<'a> From<&'a String> for Cow<'a, str> {
     #[inline]
     fn from(s: &'a String) -> Cow<'a, str> {
diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs
index 315a8a0aad07f..be4c80c85d997 100644
--- a/src/liballoc/vec.rs
+++ b/src/liballoc/vec.rs
@@ -2285,7 +2285,7 @@ impl<'a, T: Clone> From<Vec<T>> for Cow<'a, [T]> {
     }
 }
 
-#[stable(feature = "cow_from_vec_ref", since = "1.27.0")]
+#[stable(feature = "cow_from_vec_ref", since = "1.28.0")]
 impl<'a, T: Clone> From<&'a Vec<T>> for Cow<'a, [T]> {
     fn from(v: &'a Vec<T>) -> Cow<'a, [T]> {
         Cow::Borrowed(v.as_slice())
diff --git a/src/libstd/ffi/c_str.rs b/src/libstd/ffi/c_str.rs
index 10f59b0a3cc2c..05ab4c3cecc01 100644
--- a/src/libstd/ffi/c_str.rs
+++ b/src/libstd/ffi/c_str.rs
@@ -682,7 +682,7 @@ impl Borrow<CStr> for CString {
     fn borrow(&self) -> &CStr { self }
 }
 
-#[stable(feature = "cstring_from_cow_cstr", since = "1.27.0")]
+#[stable(feature = "cstring_from_cow_cstr", since = "1.2780")]
 impl<'a> From<Cow<'a, CStr>> for CString {
     #[inline]
     fn from(s: Cow<'a, CStr>) -> Self {
@@ -714,7 +714,7 @@ impl From<CString> for Box<CStr> {
     }
 }
 
-#[stable(feature = "cow_from_cstr", since = "1.27.0")]
+#[stable(feature = "cow_from_cstr", since = "1.28.0")]
 impl<'a> From<CString> for Cow<'a, CStr> {
     #[inline]
     fn from(s: CString) -> Cow<'a, CStr> {
@@ -722,7 +722,7 @@ impl<'a> From<CString> for Cow<'a, CStr> {
     }
 }
 
-#[stable(feature = "cow_from_cstr", since = "1.27.0")]
+#[stable(feature = "cow_from_cstr", since = "1.28.0")]
 impl<'a> From<&'a CStr> for Cow<'a, CStr> {
     #[inline]
     fn from(s: &'a CStr) -> Cow<'a, CStr> {
@@ -730,7 +730,7 @@ impl<'a> From<&'a CStr> for Cow<'a, CStr> {
     }
 }
 
-#[stable(feature = "cow_from_cstr", since = "1.27.0")]
+#[stable(feature = "cow_from_cstr", since = "1.28.0")]
 impl<'a> From<&'a CString> for Cow<'a, CStr> {
     #[inline]
     fn from(s: &'a CString) -> Cow<'a, CStr> {
diff --git a/src/libstd/ffi/os_str.rs b/src/libstd/ffi/os_str.rs
index d865ffa8e2f81..0a3148029d053 100644
--- a/src/libstd/ffi/os_str.rs
+++ b/src/libstd/ffi/os_str.rs
@@ -664,7 +664,7 @@ impl<'a> From<&'a OsStr> for Rc<OsStr> {
     }
 }
 
-#[stable(feature = "cow_from_osstr", since = "1.27.0")]
+#[stable(feature = "cow_from_osstr", since = "1.28.0")]
 impl<'a> From<OsString> for Cow<'a, OsStr> {
     #[inline]
     fn from(s: OsString) -> Cow<'a, OsStr> {
@@ -672,7 +672,7 @@ impl<'a> From<OsString> for Cow<'a, OsStr> {
     }
 }
 
-#[stable(feature = "cow_from_osstr", since = "1.27.0")]
+#[stable(feature = "cow_from_osstr", since = "1.28.0")]
 impl<'a> From<&'a OsStr> for Cow<'a, OsStr> {
     #[inline]
     fn from(s: &'a OsStr) -> Cow<'a, OsStr> {
@@ -680,7 +680,7 @@ impl<'a> From<&'a OsStr> for Cow<'a, OsStr> {
     }
 }
 
-#[stable(feature = "cow_from_osstr", since = "1.27.0")]
+#[stable(feature = "cow_from_osstr", since = "1.28.0")]
 impl<'a> From<&'a OsString> for Cow<'a, OsStr> {
     #[inline]
     fn from(s: &'a OsString) -> Cow<'a, OsStr> {
@@ -688,7 +688,7 @@ impl<'a> From<&'a OsString> for Cow<'a, OsStr> {
     }
 }
 
-#[stable(feature = "osstring_from_cow_osstr", since = "1.27.0")]
+#[stable(feature = "osstring_from_cow_osstr", since = "1.28.0")]
 impl<'a> From<Cow<'a, OsStr>> for OsString {
     #[inline]
     fn from(s: Cow<'a, OsStr>) -> Self {
diff --git a/src/libstd/path.rs b/src/libstd/path.rs
index 83633210ff2cb..b7ab14b29ca37 100644
--- a/src/libstd/path.rs
+++ b/src/libstd/path.rs
@@ -1532,7 +1532,7 @@ impl<'a> From<PathBuf> for Cow<'a, Path> {
     }
 }
 
-#[stable(feature = "cow_from_pathbuf_ref", since = "1.27.0")]
+#[stable(feature = "cow_from_pathbuf_ref", since = "1.28.0")]
 impl<'a> From<&'a PathBuf> for Cow<'a, Path> {
     #[inline]
     fn from(p: &'a PathBuf) -> Cow<'a, Path> {
@@ -1540,7 +1540,7 @@ impl<'a> From<&'a PathBuf> for Cow<'a, Path> {
     }
 }
 
-#[stable(feature = "pathbuf_from_cow_path", since = "1.27.0")]
+#[stable(feature = "pathbuf_from_cow_path", since = "1.28.0")]
 impl<'a> From<Cow<'a, Path>> for PathBuf {
     #[inline]
     fn from(p: Cow<'a, Path>) -> Self {