diff --git a/libc/include/android/dlext.h b/libc/include/android/dlext.h
index f216aab..a5061c7 100644
--- a/libc/include/android/dlext.h
+++ b/libc/include/android/dlext.h
@@ -177,11 +177,8 @@
  * Opens the given library. The `__filename` and `__flags` arguments are
  * the same as for [dlopen(3)](http://man7.org/linux/man-pages/man3/dlopen.3.html),
  * with the Android-specific flags supplied via the `flags` member of `__info`.
- *
- * Available since API level 21.
  */
-void* _Nullable android_dlopen_ext(const char* _Nullable __filename, int __flags, const android_dlextinfo* _Nullable __info)
-  __INTRODUCED_IN(21);
+void* _Nullable android_dlopen_ext(const char* _Nullable __filename, int __flags, const android_dlextinfo* _Nullable __info);
 
 __END_DECLS
 
diff --git a/libc/include/android/set_abort_message.h b/libc/include/android/set_abort_message.h
index 2be01a9..35867ac 100644
--- a/libc/include/android/set_abort_message.h
+++ b/libc/include/android/set_abort_message.h
@@ -43,9 +43,7 @@
  * This is meant for use by libraries that deliberately abort so that they can
  * provide an explanation. It is used within bionic to implement assert() and
  * all FORTIFY/fdsan aborts.
- *
- * Available since API level 21.
  */
-void android_set_abort_message(const char* _Nullable __msg) __INTRODUCED_IN(21);
+void android_set_abort_message(const char* _Nullable __msg);
 
 __END_DECLS
diff --git a/libc/include/arpa/inet.h b/libc/include/arpa/inet.h
index 748b7a1..f00f2c1 100644
--- a/libc/include/arpa/inet.h
+++ b/libc/include/arpa/inet.h
@@ -38,10 +38,10 @@
 
 in_addr_t inet_addr(const char* _Nonnull __s);
 int inet_aton(const char* _Nonnull __s, struct in_addr* _Nullable __addr);
-in_addr_t inet_lnaof(struct in_addr __addr) __INTRODUCED_IN(21);
-struct in_addr inet_makeaddr(in_addr_t __net, in_addr_t __host) __INTRODUCED_IN(21);
-in_addr_t inet_netof(struct in_addr __addr) __INTRODUCED_IN(21);
-in_addr_t inet_network(const char* _Nonnull __s) __INTRODUCED_IN(21);
+in_addr_t inet_lnaof(struct in_addr __addr);
+struct in_addr inet_makeaddr(in_addr_t __net, in_addr_t __host);
+in_addr_t inet_netof(struct in_addr __addr);
+in_addr_t inet_network(const char* _Nonnull __s);
 char* _Nonnull inet_ntoa(struct in_addr __addr);
 const char* _Nullable inet_ntop(int __af, const void* _Nonnull __src, char* _Nonnull __dst, socklen_t __size);
 unsigned int inet_nsap_addr(const char* _Nonnull __ascii, unsigned char* _Nonnull __binary, int __n);
diff --git a/libc/include/bits/fortify/fcntl.h b/libc/include/bits/fortify/fcntl.h
index ce600ff..05c62eb 100644
--- a/libc/include/bits/fortify/fcntl.h
+++ b/libc/include/bits/fortify/fcntl.h
@@ -30,8 +30,8 @@
 #error "Never include this file directly; instead, include <fcntl.h>"
 #endif
 
-int __open_2(const char* _Nonnull, int) __INTRODUCED_IN(17);
-int __openat_2(int, const char* _Nonnull, int) __INTRODUCED_IN(17);
+int __open_2(const char* _Nonnull, int);
+int __openat_2(int, const char* _Nonnull, int);
 /*
  * These are the easiest way to call the real open even in clang FORTIFY.
  */
diff --git a/libc/include/bits/fortify/socket.h b/libc/include/bits/fortify/socket.h
index 8297580..02f94cc 100644
--- a/libc/include/bits/fortify/socket.h
+++ b/libc/include/bits/fortify/socket.h
@@ -32,8 +32,7 @@
 
 extern ssize_t __sendto_chk(int, const void* _Nonnull, size_t, size_t, int, const struct sockaddr* _Nullable,
         socklen_t) __INTRODUCED_IN(26);
-ssize_t __recvfrom_chk(int, void* _Nullable, size_t, size_t, int, struct sockaddr* _Nullable,
-        socklen_t* _Nullable) __INTRODUCED_IN(21);
+ssize_t __recvfrom_chk(int, void* _Nullable, size_t, size_t, int, struct sockaddr* _Nullable, socklen_t* _Nullable);
 
 #if defined(__BIONIC_FORTIFY)
 
diff --git a/libc/include/bits/fortify/stat.h b/libc/include/bits/fortify/stat.h
index 9b4ade2..378072c 100644
--- a/libc/include/bits/fortify/stat.h
+++ b/libc/include/bits/fortify/stat.h
@@ -28,7 +28,7 @@
 
 #pragma once
 
-mode_t __umask_chk(mode_t) __INTRODUCED_IN(18);
+mode_t __umask_chk(mode_t);
 mode_t __umask_real(mode_t mode) __RENAME(umask);
 
 #if defined(__BIONIC_FORTIFY)
diff --git a/libc/include/bits/fortify/stdio.h b/libc/include/bits/fortify/stdio.h
index 578d04c..e4607e0 100644
--- a/libc/include/bits/fortify/stdio.h
+++ b/libc/include/bits/fortify/stdio.h
@@ -30,7 +30,7 @@
 #error "Never include this file directly; instead, include <stdio.h>"
 #endif
 
-char* _Nullable __fgets_chk(char* _Nonnull, int, FILE* _Nonnull, size_t) __INTRODUCED_IN(17);
+char* _Nullable __fgets_chk(char* _Nonnull, int, FILE* _Nonnull, size_t);
 size_t __fread_chk(void* _Nonnull, size_t, size_t, FILE* _Nonnull, size_t) __INTRODUCED_IN(24);
 size_t __fwrite_chk(const void* _Nonnull, size_t, size_t, FILE* _Nonnull, size_t) __INTRODUCED_IN(24);
 
diff --git a/libc/include/bits/fortify/string.h b/libc/include/bits/fortify/string.h
index 3dc1cca..7df0b05 100644
--- a/libc/include/bits/fortify/string.h
+++ b/libc/include/bits/fortify/string.h
@@ -32,10 +32,10 @@
 
 void* _Nullable __memchr_chk(const void* _Nonnull, int, size_t, size_t) __INTRODUCED_IN(23);
 void* _Nullable __memrchr_chk(const void* _Nonnull, int, size_t, size_t) __INTRODUCED_IN(23);
-char* _Nonnull __stpncpy_chk2(char* _Nonnull, const char* _Nonnull, size_t, size_t, size_t) __INTRODUCED_IN(21);
-char* _Nonnull __strncpy_chk2(char* _Nonnull, const char* _Nonnull, size_t, size_t, size_t) __INTRODUCED_IN(21);
-size_t __strlcpy_chk(char* _Nonnull, const char* _Nonnull, size_t, size_t) __INTRODUCED_IN(17);
-size_t __strlcat_chk(char* _Nonnull, const char* _Nonnull, size_t, size_t) __INTRODUCED_IN(17);
+char* _Nonnull __stpncpy_chk2(char* _Nonnull, const char* _Nonnull, size_t, size_t, size_t);
+char* _Nonnull __strncpy_chk2(char* _Nonnull, const char* _Nonnull, size_t, size_t, size_t);
+size_t __strlcpy_chk(char* _Nonnull, const char* _Nonnull, size_t, size_t);
+size_t __strlcat_chk(char* _Nonnull, const char* _Nonnull, size_t, size_t);
 
 #if defined(__BIONIC_FORTIFY)
 extern void* _Nullable __memrchr_real(const void* _Nonnull, int, size_t) __RENAME(memrchr);
diff --git a/libc/include/bits/fortify/unistd.h b/libc/include/bits/fortify/unistd.h
index bbc228d..7eda1a6 100644
--- a/libc/include/bits/fortify/unistd.h
+++ b/libc/include/bits/fortify/unistd.h
@@ -43,7 +43,7 @@
 ssize_t __pwrite64_chk(int, const void* _Nonnull, size_t, off64_t, size_t) __INTRODUCED_IN(24);
 ssize_t __pwrite64_real(int, const void* _Nonnull, size_t, off64_t) __RENAME(pwrite64);
 
-ssize_t __read_chk(int, void* __BIONIC_COMPLICATED_NULLNESS, size_t, size_t) __INTRODUCED_IN(21);
+ssize_t __read_chk(int, void* __BIONIC_COMPLICATED_NULLNESS, size_t, size_t);
 ssize_t __write_chk(int, const void* __BIONIC_COMPLICATED_NULLNESS, size_t, size_t) __INTRODUCED_IN(24);
 ssize_t __readlink_chk(const char* _Nonnull, char* _Nonnull, size_t, size_t) __INTRODUCED_IN(23);
 ssize_t __readlinkat_chk(int dirfd, const char* _Nonnull, char* _Nonnull, size_t, size_t) __INTRODUCED_IN(23);
diff --git a/libc/include/bits/wctype.h b/libc/include/bits/wctype.h
index 3abbf82..11d5fde 100644
--- a/libc/include/bits/wctype.h
+++ b/libc/include/bits/wctype.h
@@ -39,7 +39,7 @@
 
 int iswalnum(wint_t __wc);
 int iswalpha(wint_t __wc);
-int iswblank(wint_t __wc) __INTRODUCED_IN(21);
+int iswblank(wint_t __wc);
 int iswcntrl(wint_t __wc);
 int iswdigit(wint_t __wc);
 int iswgraph(wint_t __wc);
diff --git a/libc/include/dirent.h b/libc/include/dirent.h
index 2751b9e..4f5d0fb 100644
--- a/libc/include/dirent.h
+++ b/libc/include/dirent.h
@@ -123,10 +123,10 @@
  * or returns null and leaves `errno` unchanged at the end of the directory,
  * or returns null and sets `errno` on failure.
  */
-struct dirent64* _Nullable readdir64(DIR* _Nonnull __dir) __INTRODUCED_IN(21);
+struct dirent64* _Nullable readdir64(DIR* _Nonnull __dir);
 
 int readdir_r(DIR* _Nonnull __dir, struct dirent* _Nonnull __entry, struct dirent* _Nullable * _Nonnull __buffer) __attribute__((__deprecated__("readdir_r is deprecated; use readdir instead")));
-int readdir64_r(DIR* _Nonnull __dir, struct dirent64* _Nonnull __entry, struct dirent64* _Nullable * _Nonnull __buffer) __INTRODUCED_IN(21) __attribute__((__deprecated__("readdir64_r is deprecated; use readdir64 instead")));
+int readdir64_r(DIR* _Nonnull __dir, struct dirent64* _Nonnull __entry, struct dirent64* _Nullable * _Nonnull __buffer) __attribute__((__deprecated__("readdir64_r is deprecated; use readdir64 instead")));
 
 /**
  * [closedir(3)](http://man7.org/linux/man-pages/man3/closedir.3.html)
@@ -179,10 +179,8 @@
 /**
  * [alphasort64](http://man7.org/linux/man-pages/man3/alphasort.3.html) is a
  * comparator for use with scandir64() that uses strcmp().
- *
- * Available since API level 21.
  */
-int alphasort64(const struct dirent64* _Nonnull * _Nonnull __lhs, const struct dirent64* _Nonnull * _Nonnull __rhs) __INTRODUCED_IN(21);
+int alphasort64(const struct dirent64* _Nonnull * _Nonnull __lhs, const struct dirent64* _Nonnull * _Nonnull __rhs);
 
 /**
  * [scandir(3)](http://man7.org/linux/man-pages/man3/scandir.3.html)
@@ -205,10 +203,8 @@
  *
  * Returns the number of entries returned in the list on success,
  * and returns -1 and sets `errno` on failure.
- *
- * Available since API level 21.
  */
-int scandir64(const char* _Nonnull __path, struct dirent64* _Nonnull * _Nonnull * _Nonnull __name_list, int (* _Nullable __filter)(const struct dirent64* _Nonnull), int (* _Nullable __comparator)(const struct dirent64* _Nonnull * _Nonnull, const struct dirent64* _Nonnull * _Nonnull)) __INTRODUCED_IN(21);
+int scandir64(const char* _Nonnull __path, struct dirent64* _Nonnull * _Nonnull * _Nonnull __name_list, int (* _Nullable __filter)(const struct dirent64* _Nonnull), int (* _Nullable __comparator)(const struct dirent64* _Nonnull * _Nonnull, const struct dirent64* _Nonnull * _Nonnull));
 
 #if defined(__USE_GNU)
 
diff --git a/libc/include/fcntl.h b/libc/include/fcntl.h
index a8db387..16ce6fa 100644
--- a/libc/include/fcntl.h
+++ b/libc/include/fcntl.h
@@ -111,7 +111,7 @@
  */
 int creat(const char* _Nonnull __path, mode_t __mode);
 /** See creat(). */
-int creat64(const char* _Nonnull __path, mode_t __mode) __INTRODUCED_IN(21);
+int creat64(const char* _Nonnull __path, mode_t __mode);
 
 /**
  * [openat(2)](http://man7.org/linux/man-pages/man2/openat.2.html)
@@ -122,7 +122,7 @@
  */
 int openat(int __dir_fd, const char* _Nonnull __path, int __flags, ...);
 /** See openat(). */
-int openat64(int __dir_fd, const char* _Nonnull __path, int __flags, ...) __INTRODUCED_IN(21);
+int openat64(int __dir_fd, const char* _Nonnull __path, int __flags, ...);
 
 /**
  * [open(2)](http://man7.org/linux/man-pages/man2/open.2.html)
@@ -133,7 +133,7 @@
  */
 int open(const char* _Nonnull __path, int __flags, ...);
 /** See open(). */
-int open64(const char* _Nonnull __path, int __flags, ...) __INTRODUCED_IN(21);
+int open64(const char* _Nonnull __path, int __flags, ...);
 
 /**
  * [splice(2)](http://man7.org/linux/man-pages/man2/splice.2.html)
@@ -144,10 +144,8 @@
  *
  * Returns the number of bytes spliced on success and returns -1 and sets
  * `errno` on failure.
- *
- * Available since API level 21.
  */
-ssize_t splice(int __in_fd, off64_t* __BIONIC_COMPLICATED_NULLNESS __in_offset, int __out_fd, off64_t* __BIONIC_COMPLICATED_NULLNESS __out_offset, size_t __length, unsigned int __flags) __INTRODUCED_IN(21);
+ssize_t splice(int __in_fd, off64_t* __BIONIC_COMPLICATED_NULLNESS __in_offset, int __out_fd, off64_t* __BIONIC_COMPLICATED_NULLNESS __out_offset, size_t __length, unsigned int __flags);
 
 /**
  * [tee(2)](http://man7.org/linux/man-pages/man2/tee.2.html)
@@ -158,10 +156,8 @@
  *
  * Returns the number of bytes duplicated on success and returns -1 and sets
  * `errno` on failure.
- *
- * Available since API level 21.
  */
-ssize_t tee(int __in_fd, int __out_fd, size_t __length, unsigned int __flags) __INTRODUCED_IN(21);
+ssize_t tee(int __in_fd, int __out_fd, size_t __length, unsigned int __flags);
 
 /**
  * [vmsplice(2)](http://man7.org/linux/man-pages/man2/vmsplice.2.html)
@@ -172,10 +168,8 @@
  *
  * Returns the number of bytes spliced on success and returns -1 and sets
  * `errno` on failure.
- *
- * Available since API level 21.
  */
-ssize_t vmsplice(int __fd, const struct iovec* _Nonnull __iov, size_t __count, unsigned int __flags) __INTRODUCED_IN(21);
+ssize_t vmsplice(int __fd, const struct iovec* _Nonnull __iov, size_t __count, unsigned int __flags);
 
 /**
  * [fallocate(2)](http://man7.org/linux/man-pages/man2/fallocate.2.html)
@@ -187,12 +181,10 @@
  * `FALLOC_FL_UNSHARE_RANGE`.
  *
  * Returns 0 on success and returns -1 and sets `errno` on failure.
- *
- * Available since API level 21.
  */
-int fallocate(int __fd, int __mode, off_t __offset, off_t __length) __RENAME_IF_FILE_OFFSET64(fallocate64) __INTRODUCED_IN(21);
+int fallocate(int __fd, int __mode, off_t __offset, off_t __length) __RENAME_IF_FILE_OFFSET64(fallocate64);
 /** See fallocate(). */
-int fallocate64(int __fd, int __mode, off64_t __offset, off64_t __length) __INTRODUCED_IN(21);
+int fallocate64(int __fd, int __mode, off64_t __offset, off64_t __length);
 
 /**
  * [posix_fadvise(2)](http://man7.org/linux/man-pages/man2/posix_fadvise.2.html)
@@ -203,24 +195,20 @@
  * and `POSIX_FADV_NOREUSE`.
  *
  * Returns 0 on success and returns an error number on failure.
- *
- * Available since API level 21.
  */
-int posix_fadvise(int __fd, off_t __offset, off_t __length, int __advice) __RENAME_IF_FILE_OFFSET64(posix_fadvise64) __INTRODUCED_IN(21);
+int posix_fadvise(int __fd, off_t __offset, off_t __length, int __advice) __RENAME_IF_FILE_OFFSET64(posix_fadvise64);
 /** See posix_fadvise(). */
-int posix_fadvise64(int __fd, off64_t __offset, off64_t __length, int __advice) __INTRODUCED_IN(21);
+int posix_fadvise64(int __fd, off64_t __offset, off64_t __length, int __advice);
 
 /**
  * [posix_fallocate(2)](http://man7.org/linux/man-pages/man2/posix_fallocate.2.html)
  * allocates file space.
  *
  * Returns 0 on success and returns an error number on failure.
- *
- * Available since API level 21.
  */
-int posix_fallocate(int __fd, off_t __offset, off_t __length) __RENAME_IF_FILE_OFFSET64(posix_fallocate64) __INTRODUCED_IN(21);
+int posix_fallocate(int __fd, off_t __offset, off_t __length) __RENAME_IF_FILE_OFFSET64(posix_fallocate64);
 /** See posix_fallocate(). */
-int posix_fallocate64(int __fd, off64_t __offset, off64_t __length) __INTRODUCED_IN(21);
+int posix_fallocate64(int __fd, off64_t __offset, off64_t __length);
 
 #if defined(__USE_GNU)
 
diff --git a/libc/include/fts.h b/libc/include/fts.h
index bae2615..8dfd213 100644
--- a/libc/include/fts.h
+++ b/libc/include/fts.h
@@ -117,16 +117,11 @@
 
 __BEGIN_DECLS
 
-/*
- * Strictly these functions were available before Lollipop/21, but there was an accidental ABI
- * breakage in 21 that means you can't write code that runs on current devices and pre-21 devices,
- * so we break the tie in favor of current and future devices.
- */
-FTSENT* _Nullable fts_children(FTS* _Nonnull __fts, int __options) __INTRODUCED_IN(21);
-int fts_close(FTS* _Nonnull __fts) __INTRODUCED_IN(21);
-FTS* _Nullable fts_open(char* _Nonnull const* _Nonnull __path, int __options, int (* _Nullable __comparator)(const FTSENT* _Nonnull * _Nonnull  __lhs, const FTSENT* _Nonnull * _Nonnull __rhs)) __INTRODUCED_IN(21);
-FTSENT* _Nullable fts_read(FTS* _Nonnull __fts) __INTRODUCED_IN(21);
-int fts_set(FTS* _Nonnull __fts, FTSENT* _Nonnull __entry, int __options) __INTRODUCED_IN(21);
+FTSENT* _Nullable fts_children(FTS* _Nonnull __fts, int __options);
+int fts_close(FTS* _Nonnull __fts);
+FTS* _Nullable fts_open(char* _Nonnull const* _Nonnull __path, int __options, int (* _Nullable __comparator)(const FTSENT* _Nonnull * _Nonnull  __lhs, const FTSENT* _Nonnull * _Nonnull __rhs));
+FTSENT* _Nullable fts_read(FTS* _Nonnull __fts);
+int fts_set(FTS* _Nonnull __fts, FTSENT* _Nonnull __entry, int __options);
 
 __END_DECLS
 
diff --git a/libc/include/ftw.h b/libc/include/ftw.h
index ee154f0..ac2473a 100644
--- a/libc/include/ftw.h
+++ b/libc/include/ftw.h
@@ -55,10 +55,10 @@
 };
 
 __BEGIN_DECLS
-int ftw(const char* _Nonnull __dir_path, int (* _Nonnull __callback)(const char* _Nonnull, const struct stat* _Nonnull, int), int __max_fd_count) __INTRODUCED_IN(17);
-int nftw(const char* _Nonnull __dir_path, int (* _Nonnull __callback)(const char* _Nonnull, const struct stat* _Nonnull, int, struct FTW* _Nonnull), int __max_fd_count, int __flags) __INTRODUCED_IN(17);
-int ftw64(const char* _Nonnull __dir_path, int (* _Nonnull __callback)(const char* _Nonnull, const struct stat64* _Nonnull, int), int __max_fd_count) __INTRODUCED_IN(21);
-int nftw64(const char* _Nonnull __dir_path, int (* _Nonnull __callback)(const char* _Nonnull, const struct stat64* _Nonnull, int, struct FTW* _Nonnull), int __max_fd_count, int __flags) __INTRODUCED_IN(21);
+int ftw(const char* _Nonnull __dir_path, int (* _Nonnull __callback)(const char* _Nonnull, const struct stat* _Nonnull, int), int __max_fd_count);
+int nftw(const char* _Nonnull __dir_path, int (* _Nonnull __callback)(const char* _Nonnull, const struct stat* _Nonnull, int, struct FTW* _Nonnull), int __max_fd_count, int __flags);
+int ftw64(const char* _Nonnull __dir_path, int (* _Nonnull __callback)(const char* _Nonnull, const struct stat64* _Nonnull, int), int __max_fd_count);
+int nftw64(const char* _Nonnull __dir_path, int (* _Nonnull __callback)(const char* _Nonnull, const struct stat64* _Nonnull, int, struct FTW* _Nonnull), int __max_fd_count, int __flags);
 __END_DECLS
 
 #endif
diff --git a/libc/include/inttypes.h b/libc/include/inttypes.h
index 76aee38..9fcd9f3 100644
--- a/libc/include/inttypes.h
+++ b/libc/include/inttypes.h
@@ -327,12 +327,12 @@
 } imaxdiv_t;
 
 __BEGIN_DECLS
-intmax_t imaxabs(intmax_t __i) __attribute_const__ __INTRODUCED_IN(19);
-imaxdiv_t imaxdiv(intmax_t __numerator, intmax_t __denominator) __attribute_const__ __INTRODUCED_IN(19);
+intmax_t imaxabs(intmax_t __i) __attribute_const__;
+imaxdiv_t imaxdiv(intmax_t __numerator, intmax_t __denominator) __attribute_const__;
 intmax_t strtoimax(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, int __base);
 uintmax_t strtoumax(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, int __base);
-intmax_t wcstoimax(const wchar_t* _Nonnull __s, wchar_t* _Nullable * _Nullable __end_ptr, int __base) __INTRODUCED_IN(21);
-uintmax_t wcstoumax(const wchar_t* _Nonnull __s, wchar_t* _Nullable * _Nullable __end_ptr, int __base) __INTRODUCED_IN(21);
+intmax_t wcstoimax(const wchar_t* _Nonnull __s, wchar_t* _Nullable * _Nullable __end_ptr, int __base);
+uintmax_t wcstoumax(const wchar_t* _Nonnull __s, wchar_t* _Nullable * _Nullable __end_ptr, int __base);
 __END_DECLS
 
 #endif
diff --git a/libc/include/link.h b/libc/include/link.h
index a0a3d60..33fea49 100644
--- a/libc/include/link.h
+++ b/libc/include/link.h
@@ -55,11 +55,7 @@
   void* _Nullable dlpi_tls_data;
 };
 
-#if defined(__arm__)
-int dl_iterate_phdr(int (* _Nonnull __callback)(struct dl_phdr_info* _Nonnull, size_t, void* _Nullable), void* _Nullable __data) __INTRODUCED_IN(21);
-#else
-int dl_iterate_phdr(int (* _Nonnull __callback)(struct dl_phdr_info* _Nonnull, size_t, void*_Nullable ), void* _Nullable __data);
-#endif
+int dl_iterate_phdr(int (* _Nonnull __callback)(struct dl_phdr_info* _Nonnull, size_t, void* _Nullable), void* _Nullable __data);
 
 #ifdef __arm__
 typedef uintptr_t _Unwind_Ptr;
diff --git a/libc/include/locale.h b/libc/include/locale.h
index 27f2a3f..6100765 100644
--- a/libc/include/locale.h
+++ b/libc/include/locale.h
@@ -98,11 +98,11 @@
 
 struct lconv* _Nonnull localeconv(void) __INTRODUCED_IN_NO_GUARD_FOR_NDK(21);
 
-locale_t _Nullable duplocale(locale_t _Nonnull __l) __INTRODUCED_IN(21);
-void freelocale(locale_t _Nonnull __l) __INTRODUCED_IN(21);
-locale_t _Nullable newlocale(int __category_mask, const char* _Nonnull __locale_name, locale_t _Nullable __base) __INTRODUCED_IN(21);
+locale_t _Nullable duplocale(locale_t _Nonnull __l);
+void freelocale(locale_t _Nonnull __l);
+locale_t _Nullable newlocale(int __category_mask, const char* _Nonnull __locale_name, locale_t _Nullable __base);
 char* _Nullable setlocale(int __category, const char* _Nullable __locale_name);
-locale_t _Nullable uselocale(locale_t _Nullable __l) __INTRODUCED_IN(21);
+locale_t _Nullable uselocale(locale_t _Nullable __l);
 
 #define LC_GLOBAL_LOCALE __BIONIC_CAST(reinterpret_cast, locale_t, -1L)
 
diff --git a/libc/include/malloc.h b/libc/include/malloc.h
index 91d63b3..c5d297b 100644
--- a/libc/include/malloc.h
+++ b/libc/include/malloc.h
@@ -92,10 +92,8 @@
 /**
  * [malloc_usable_size(3)](http://man7.org/linux/man-pages/man3/malloc_usable_size.3.html)
  * returns the actual size of the given heap block.
- *
- * Available since API level 17.
  */
-size_t malloc_usable_size(const void* _Nullable __ptr) __INTRODUCED_IN(17);
+size_t malloc_usable_size(const void* _Nullable __ptr);
 
 #define __MALLINFO_BODY \
   /** Total number of non-mmapped bytes currently allocated from OS. */ \
diff --git a/libc/include/math.h b/libc/include/math.h
index 0572238..fc6c228 100644
--- a/libc/include/math.h
+++ b/libc/include/math.h
@@ -161,8 +161,8 @@
 float log1pf(float __x);
 long double log1pl(long double __x);
 
-double log2(double __x) __INTRODUCED_IN(18);
-float log2f(float __x) __INTRODUCED_IN(18);
+double log2(double __x);
+float log2f(float __x);
 long double log2l(long double __x);
 
 double logb(double __x);
@@ -319,7 +319,7 @@
  * to the std namespace, making it impossible to use both <cmath> (which gets
  * included by a lot of other standard headers) and ::isnan.
  */
-int (isinf)(double __x) __attribute_const__ __INTRODUCED_IN(21);
+int (isinf)(double __x) __attribute_const__;
 int (isnan)(double __x) __attribute_const__;
 
 /* POSIX extensions. */
@@ -367,7 +367,7 @@
 double lgamma_r(double __x, int* _Nonnull __sign);
 double significand(double __x);
 long double lgammal_r(long double __x, int* _Nonnull __sign) __INTRODUCED_IN(23);
-long double significandl(long double __x) __INTRODUCED_IN(21);
+long double significandl(long double __x);
 float dremf(float __x, float __y);
 int finitef(float __x) __attribute_const__;
 float gammaf(float __x);
diff --git a/libc/include/mntent.h b/libc/include/mntent.h
index 43cab1f..9a31838 100644
--- a/libc/include/mntent.h
+++ b/libc/include/mntent.h
@@ -57,10 +57,10 @@
 
 __BEGIN_DECLS
 
-int endmntent(FILE* _Nullable __fp) __INTRODUCED_IN(21);
+int endmntent(FILE* _Nullable __fp);
 struct mntent* _Nullable getmntent(FILE* _Nonnull __fp);
-struct mntent* _Nullable getmntent_r(FILE* _Nonnull __fp, struct mntent* _Nonnull __entry, char* _Nonnull __buf, int __size) __INTRODUCED_IN(21);
-FILE* _Nullable setmntent(const char* _Nonnull __filename, const char* _Nonnull __type) __INTRODUCED_IN(21);
+struct mntent* _Nullable getmntent_r(FILE* _Nonnull __fp, struct mntent* _Nonnull __entry, char* _Nonnull __buf, int __size);
+FILE* _Nullable setmntent(const char* _Nonnull __filename, const char* _Nonnull __type);
 char* _Nullable hasmntopt(const struct mntent* _Nonnull __entry, const char* _Nonnull __option) __INTRODUCED_IN(26);
 
 __END_DECLS
diff --git a/libc/include/poll.h b/libc/include/poll.h
index e3a9039..6bdc886 100644
--- a/libc/include/poll.h
+++ b/libc/include/poll.h
@@ -58,10 +58,8 @@
  *
  * Returns the number of ready file descriptors on success, 0 for timeout,
  * and returns -1 and sets `errno` on failure.
- *
- * Available since API level 28.
  */
-int ppoll(struct pollfd* _Nullable __fds, nfds_t __count, const struct timespec* _Nullable __timeout, const sigset_t* _Nullable __mask) __INTRODUCED_IN(21);
+int ppoll(struct pollfd* _Nullable __fds, nfds_t __count, const struct timespec* _Nullable __timeout, const sigset_t* _Nullable __mask);
 
 /**
  * Like ppoll() but allows setting a signal mask with RT signals even from a 32-bit process.
diff --git a/libc/include/pthread.h b/libc/include/pthread.h
index 98695eb..1f08628 100644
--- a/libc/include/pthread.h
+++ b/libc/include/pthread.h
@@ -116,10 +116,10 @@
 int pthread_attr_setstacksize(pthread_attr_t* _Nonnull __addr, size_t __size);
 
 int pthread_condattr_destroy(pthread_condattr_t* _Nonnull __attr);
-int pthread_condattr_getclock(const pthread_condattr_t* _Nonnull __attr, clockid_t* _Nonnull __clock) __INTRODUCED_IN(21);
+int pthread_condattr_getclock(const pthread_condattr_t* _Nonnull __attr, clockid_t* _Nonnull __clock);
 int pthread_condattr_getpshared(const pthread_condattr_t* _Nonnull __attr, int* _Nonnull __shared);
 int pthread_condattr_init(pthread_condattr_t* _Nonnull __attr);
-int pthread_condattr_setclock(pthread_condattr_t* _Nonnull __attr, clockid_t __clock) __INTRODUCED_IN(21);
+int pthread_condattr_setclock(pthread_condattr_t* _Nonnull __attr, clockid_t __clock);
 int pthread_condattr_setpshared(pthread_condattr_t* _Nonnull __attr, int __shared);
 
 int pthread_cond_broadcast(pthread_cond_t* _Nonnull __cond);
@@ -169,7 +169,7 @@
 
 void* _Nullable pthread_getspecific(pthread_key_t __key);
 
-pid_t pthread_gettid_np(pthread_t __pthread) __INTRODUCED_IN(21);
+pid_t pthread_gettid_np(pthread_t __pthread);
 
 int pthread_join(pthread_t __pthread, void* _Nullable * _Nullable __return_value_ptr);
 
@@ -190,8 +190,7 @@
 int pthread_mutex_destroy(pthread_mutex_t* _Nonnull __mutex);
 int pthread_mutex_init(pthread_mutex_t* _Nonnull __mutex, const pthread_mutexattr_t* _Nullable __attr);
 int pthread_mutex_lock(pthread_mutex_t* _Nonnull __mutex);
-int pthread_mutex_timedlock(pthread_mutex_t* _Nonnull __mutex, const struct timespec* _Nullable __timeout)
-  __INTRODUCED_IN(21);
+int pthread_mutex_timedlock(pthread_mutex_t* _Nonnull __mutex, const struct timespec* _Nullable __timeout);
 
 /*
  * POSIX historically only supported using pthread_mutex_timedlock() with CLOCK_REALTIME, however
diff --git a/libc/include/sched.h b/libc/include/sched.h
index d11fddf..b1f1842 100644
--- a/libc/include/sched.h
+++ b/libc/include/sched.h
@@ -179,20 +179,16 @@
  * disassociates part of the caller's execution context.
  *
  * Returns 0 on success and returns -1 and sets `errno` on failure.
- *
- * Available since API level 17.
  */
-int unshare(int __flags) __INTRODUCED_IN(17);
+int unshare(int __flags);
 
 /**
  * [setns(2)](http://man7.org/linux/man-pages/man2/setns.2.html)
  * reassociates a thread with a different namespace.
  *
  * Returns 0 on success and returns -1 and sets `errno` on failure.
- *
- * Available since API level 21.
  */
-int setns(int __fd, int __ns_type) __INTRODUCED_IN(21);
+int setns(int __fd, int __ns_type);
 
 /**
  * [sched_getcpu(3)](http://man7.org/linux/man-pages/man3/sched_getcpu.3.html)
diff --git a/libc/include/search.h b/libc/include/search.h
index 00deef1..fe897d1 100644
--- a/libc/include/search.h
+++ b/libc/include/search.h
@@ -66,18 +66,14 @@
 /**
  * [insque(3)](http://man7.org/linux/man-pages/man3/insque.3.html) inserts
  * an item in a queue (an intrusive doubly-linked list).
- *
- * Available since API level 21.
  */
-void insque(void* _Nonnull __element, void* _Nullable __previous) __INTRODUCED_IN(21);
+void insque(void* _Nonnull __element, void* _Nullable __previous);
 
 /**
  * [remque(3)](http://man7.org/linux/man-pages/man3/remque.3.html) removes
  * an item from a queue (an intrusive doubly-linked list).
- *
- * Available since API level 21.
  */
-void remque(void* _Nonnull __element) __INTRODUCED_IN(21);
+void remque(void* _Nonnull __element);
 
 /**
  * [hcreate(3)](http://man7.org/linux/man-pages/man3/hcreate.3.html)
@@ -155,10 +151,8 @@
  * See bsearch() if you have a sorted array.
  *
  * Returns a pointer to the matching element on success, or NULL on failure.
- *
- * Available since API level 21.
  */
-void* _Nullable lfind(const void* _Nonnull __key, const void* _Nonnull __array, size_t* _Nonnull __count, size_t __size, int (* _Nonnull __comparator)(const void* _Nonnull, const void* _Nonnull)) __INTRODUCED_IN(21);
+void* _Nullable lfind(const void* _Nonnull __key, const void* _Nonnull __array, size_t* _Nonnull __count, size_t __size, int (* _Nonnull __comparator)(const void* _Nonnull, const void* _Nonnull));
 
 /**
  * [lsearch(3)](http://man7.org/linux/man-pages/man3/lsearch.3.html) brute-force
@@ -170,10 +164,8 @@
  *
  * Returns a pointer to the matching element on success, or to the newly-added
  * element on failure.
- *
- * Available since API level 21.
  */
-void* _Nonnull lsearch(const void* _Nonnull __key, void* _Nonnull __array, size_t* _Nonnull __count, size_t __size, int (* _Nonnull __comparator)(const void* _Nonnull, const void* _Nonnull)) __INTRODUCED_IN(21);
+void* _Nonnull lsearch(const void* _Nonnull __key, void* _Nonnull __array, size_t* _Nonnull __count, size_t __size, int (* _Nonnull __comparator)(const void* _Nonnull, const void* _Nonnull));
 
 /**
  * [tdelete(3)](http://man7.org/linux/man-pages/man3/tdelete.3.html) searches
@@ -214,6 +206,6 @@
  * [twalk(3)](http://man7.org/linux/man-pages/man3/twalk.3.html) calls
  * `__visitor` on every node in the tree.
  */
-void twalk(const void* _Nullable __root, void (* _Nullable __visitor)(const void* _Nullable, VISIT, int)) __INTRODUCED_IN(21);
+void twalk(const void* _Nullable __root, void (* _Nullable __visitor)(const void* _Nullable, VISIT, int));
 
 __END_DECLS
diff --git a/libc/include/signal.h b/libc/include/signal.h
index b9aeaab..cf83db8 100644
--- a/libc/include/signal.h
+++ b/libc/include/signal.h
@@ -51,8 +51,8 @@
 /* We take a few real-time signals for ourselves. May as well use the same names as glibc. */
 #define SIGRTMIN (__libc_current_sigrtmin())
 #define SIGRTMAX (__libc_current_sigrtmax())
-int __libc_current_sigrtmin(void) __INTRODUCED_IN(21);
-int __libc_current_sigrtmax(void) __INTRODUCED_IN(21);
+int __libc_current_sigrtmin(void);
+int __libc_current_sigrtmax(void);
 
 extern const char* _Nonnull const sys_siglist[_NSIG];
 extern const char* _Nonnull const sys_signame[_NSIG]; /* BSD compatibility. */
@@ -64,16 +64,16 @@
 
 int siginterrupt(int __signal, int __flag);
 
-sighandler_t _Nonnull signal(int __signal, sighandler_t _Nullable __handler) __INTRODUCED_IN(21);
-int sigaddset(sigset_t* _Nonnull __set, int __signal) __INTRODUCED_IN(21);
+sighandler_t _Nonnull signal(int __signal, sighandler_t _Nullable __handler);
+int sigaddset(sigset_t* _Nonnull __set, int __signal);
 int sigaddset64(sigset64_t* _Nonnull __set, int __signal) __INTRODUCED_IN(28);
-int sigdelset(sigset_t* _Nonnull __set, int __signal) __INTRODUCED_IN(21);
+int sigdelset(sigset_t* _Nonnull __set, int __signal);
 int sigdelset64(sigset64_t* _Nonnull __set, int __signal) __INTRODUCED_IN(28);
-int sigemptyset(sigset_t* _Nonnull __set) __INTRODUCED_IN(21);
+int sigemptyset(sigset_t* _Nonnull __set);
 int sigemptyset64(sigset64_t* _Nonnull __set) __INTRODUCED_IN(28);
-int sigfillset(sigset_t* _Nonnull __set) __INTRODUCED_IN(21);
+int sigfillset(sigset_t* _Nonnull __set);
 int sigfillset64(sigset64_t* _Nonnull __set) __INTRODUCED_IN(28);
-int sigismember(const sigset_t* _Nonnull __set, int __signal) __INTRODUCED_IN(21);
+int sigismember(const sigset_t* _Nonnull __set, int __signal);
 int sigismember64(const sigset64_t* _Nonnull __set, int __signal) __INTRODUCED_IN(28);
 
 int sigpending(sigset_t* _Nonnull __set);
@@ -105,8 +105,8 @@
 
 int sigaltstack(const stack_t* _Nullable __new_signal_stack, stack_t*  _Nullable __old_signal_stack);
 
-void psiginfo(const siginfo_t* _Nonnull __info, const char* _Nullable __msg) __INTRODUCED_IN(17);
-void psignal(int __signal, const char* _Nullable __msg) __INTRODUCED_IN(17);
+void psiginfo(const siginfo_t* _Nonnull __info, const char* _Nullable __msg);
+void psignal(int __signal, const char* _Nullable __msg);
 
 int pthread_kill(pthread_t __pthread, int __signal);
 #if defined(__USE_GNU)
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index d7b65e4..2fc5b21 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -118,8 +118,8 @@
 size_t fwrite(const void* _Nonnull __buf, size_t __size, size_t __count, FILE* _Nonnull __fp);
 int getc(FILE* _Nonnull __fp);
 int getchar(void);
-ssize_t getdelim(char* _Nullable * _Nonnull __line_ptr, size_t* _Nonnull __line_length_ptr, int __delimiter, FILE* _Nonnull __fp) __INTRODUCED_IN(18);
-ssize_t getline(char* _Nullable * _Nonnull __line_ptr, size_t* _Nonnull __line_length_ptr, FILE* _Nonnull __fp) __INTRODUCED_IN(18);
+ssize_t getdelim(char* _Nullable * _Nonnull __line_ptr, size_t* _Nonnull __line_length_ptr, int __delimiter, FILE* _Nonnull __fp);
+ssize_t getline(char* _Nullable * _Nonnull __line_ptr, size_t* _Nonnull __line_length_ptr, FILE* _Nonnull __fp);
 
 void perror(const char* _Nullable __msg);
 int printf(const char* _Nonnull __fmt, ...) __printflike(1, 2);
@@ -136,8 +136,8 @@
 int vfprintf(FILE* _Nonnull __fp, const char* _Nonnull __fmt, va_list __args) __printflike(2, 0);
 int vprintf(const char* _Nonnull __fp, va_list __args) __printflike(1, 0);
 
-int dprintf(int __fd, const char* _Nonnull __fmt, ...) __printflike(2, 3) __INTRODUCED_IN(21);
-int vdprintf(int __fd, const char* _Nonnull __fmt, va_list __args) __printflike(2, 0) __INTRODUCED_IN(21);
+int dprintf(int __fd, const char* _Nonnull __fmt, ...) __printflike(2, 3);
+int vdprintf(int __fd, const char* _Nonnull __fmt, va_list __args) __printflike(2, 0);
 
 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ < 201112L) || \
     (defined(__cplusplus) && __cplusplus <= 201103L)
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index ee4b12a..a5bac61 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -43,12 +43,12 @@
 
 __noreturn void abort(void) __attribute__((__nomerge__));
 __noreturn void exit(int __status);
-__noreturn void _Exit(int __status) __INTRODUCED_IN(21);
+__noreturn void _Exit(int __status);
 
 int atexit(void (* _Nonnull __fn)(void));
 
-int at_quick_exit(void (* _Nonnull __fn)(void)) __INTRODUCED_IN(21);
-void quick_exit(int __status) __noreturn __INTRODUCED_IN(21);
+int at_quick_exit(void (* _Nonnull __fn)(void));
+void quick_exit(int __status) __noreturn;
 
 char* _Nullable getenv(const char* _Nonnull __name);
 int putenv(char* _Nonnull __assignment);
@@ -63,7 +63,7 @@
 int mkostemp(char* _Nonnull __template, int __flags) __INTRODUCED_IN(23);
 int mkostemps64(char* _Nonnull __template, int __suffix_length, int __flags) __INTRODUCED_IN(23);
 int mkostemps(char* _Nonnull __template, int __suffix_length, int __flags) __INTRODUCED_IN(23);
-int mkstemp64(char* _Nonnull __template) __INTRODUCED_IN(21);
+int mkstemp64(char* _Nonnull __template);
 int mkstemp(char* _Nonnull __template);
 int mkstemps64(char* _Nonnull __template, int __flags) __INTRODUCED_IN(23);
 int mkstemps(char* _Nonnull __template, int __flags);
@@ -73,12 +73,12 @@
 unsigned long strtoul(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, int __base);
 unsigned long long strtoull(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, int __base);
 
-int posix_memalign(void* _Nullable * _Nullable __memptr, size_t __alignment, size_t __size) __INTRODUCED_IN(17);
+int posix_memalign(void* _Nullable * _Nullable __memptr, size_t __alignment, size_t __size);
 
 void* _Nullable aligned_alloc(size_t __alignment, size_t __size) __INTRODUCED_IN(28);
 
 double strtod(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr);
-long double strtold(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr) __INTRODUCED_IN(21);
+long double strtold(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr);
 
 unsigned long strtoul_l(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, int __base, locale_t _Nonnull __l) __INTRODUCED_IN(26);
 
@@ -99,7 +99,7 @@
 
 #define RAND_MAX 0x7fffffff
 
-int rand_r(unsigned int* _Nonnull __seed_ptr) __INTRODUCED_IN(21);
+int rand_r(unsigned int* _Nonnull __seed_ptr);
 
 double drand48(void);
 double erand48(unsigned short __xsubi[_Nonnull 3]);
@@ -111,11 +111,11 @@
 unsigned short* _Nonnull seed48(unsigned short __seed16v[_Nonnull 3]);
 void srand48(long __seed);
 
-char* _Nullable initstate(unsigned int __seed, char* _Nonnull __state, size_t __n) __INTRODUCED_IN(21);
-char* _Nullable setstate(char* _Nonnull __state) __INTRODUCED_IN(21);
+char* _Nullable initstate(unsigned int __seed, char* _Nonnull __state, size_t __n);
+char* _Nullable setstate(char* _Nonnull __state);
 
 int getpt(void);
-int posix_openpt(int __flags) __INTRODUCED_IN(21);
+int posix_openpt(int __flags);
 char* _Nullable ptsname(int __fd);
 int ptsname_r(int __fd, char* _Nonnull __buf, size_t __n);
 int unlockpt(int __fd);
@@ -153,8 +153,8 @@
 int getloadavg(double __averages[_Nonnull], int __n) __INTRODUCED_IN(29);
 
 /* BSD compatibility. */
-const char* _Nullable getprogname(void) __INTRODUCED_IN(21);
-void setprogname(const char* _Nonnull __name) __INTRODUCED_IN(21);
+const char* _Nullable getprogname(void);
+void setprogname(const char* _Nonnull __name);
 
 int mblen(const char* _Nullable __s, size_t __n) __INTRODUCED_IN_NO_GUARD_FOR_NDK(26);
 size_t mbstowcs(wchar_t* _Nullable __dst, const char* _Nullable __src, size_t __n) __INTRODUCED_IN_NO_GUARD_FOR_NDK(21);
@@ -163,28 +163,28 @@
 
 size_t wcstombs(char* _Nullable __dst, const wchar_t* _Nullable __src, size_t __n) __INTRODUCED_IN_NO_GUARD_FOR_NDK(21);
 
-size_t __ctype_get_mb_cur_max(void) __INTRODUCED_IN(21);
+size_t __ctype_get_mb_cur_max(void);
 #define MB_CUR_MAX __ctype_get_mb_cur_max()
 
 #if defined(__BIONIC_INCLUDE_FORTIFY_HEADERS)
 #include <bits/fortify/stdlib.h>
 #endif
 
-int abs(int __x) __attribute_const__ __INTRODUCED_IN(19);
-long labs(long __x) __attribute_const__ __INTRODUCED_IN(19);
-long long llabs(long long __x) __attribute_const__ __INTRODUCED_IN(19);
+int abs(int __x) __attribute_const__;
+long labs(long __x) __attribute_const__;
+long long llabs(long long __x) __attribute_const__;
 
-float strtof(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr) __INTRODUCED_IN(21);
-double atof(const char* _Nonnull __s) __attribute_pure__ __INTRODUCED_IN(21);
-int rand(void) __INTRODUCED_IN(21);
-void srand(unsigned int __seed) __INTRODUCED_IN(21);
-long random(void) __INTRODUCED_IN(21);
-void srandom(unsigned int __seed) __INTRODUCED_IN(21);
-int grantpt(int __fd) __INTRODUCED_IN(21);
+float strtof(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr);
+double atof(const char* _Nonnull __s) __attribute_pure__;
+int rand(void);
+void srand(unsigned int __seed);
+long random(void);
+void srandom(unsigned int __seed);
+int grantpt(int __fd);
 
-long long strtoll_l(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, int __base, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-unsigned long long strtoull_l(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, int __base, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-long double strtold_l(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, locale_t _Nonnull __l) __INTRODUCED_IN(21);
+long long strtoll_l(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, int __base, locale_t _Nonnull __l);
+unsigned long long strtoull_l(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, int __base, locale_t _Nonnull __l);
+long double strtold_l(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, locale_t _Nonnull __l);
 
 #if __ANDROID_API__ >= 26
 double strtod_l(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr, locale_t _Nonnull __l) __INTRODUCED_IN(26);
diff --git a/libc/include/string.h b/libc/include/string.h
index d6b2967..e7fd9a5 100644
--- a/libc/include/string.h
+++ b/libc/include/string.h
@@ -76,7 +76,7 @@
 void* _Nullable memmem(const void* _Nonnull __haystack, size_t __haystack_size, const void* _Nonnull __needle, size_t __needle_size) __attribute_pure__;
 
 char* _Nullable strchr(const char* _Nonnull __s, int __ch) __attribute_pure__;
-char* _Nullable __strchr_chk(const char* _Nonnull __s, int __ch, size_t __n) __INTRODUCED_IN(18);
+char* _Nullable __strchr_chk(const char* _Nonnull __s, int __ch, size_t __n);
 #if defined(__USE_GNU)
 #if defined(__cplusplus)
 extern "C++" char* _Nonnull strchrnul(char* _Nonnull __s, int __ch) __RENAME(strchrnul) __attribute_pure__ __INTRODUCED_IN(24);
@@ -87,13 +87,13 @@
 #endif
 
 char* _Nullable strrchr(const char* _Nonnull __s, int __ch) __attribute_pure__;
-char* _Nullable __strrchr_chk(const char* _Nonnull __s, int __ch, size_t __n) __INTRODUCED_IN(18);
+char* _Nullable __strrchr_chk(const char* _Nonnull __s, int __ch, size_t __n);
 
 size_t strlen(const char* _Nonnull __s) __attribute_pure__;
-size_t __strlen_chk(const char* _Nonnull __s, size_t __n) __INTRODUCED_IN(17);
+size_t __strlen_chk(const char* _Nonnull __s, size_t __n);
 
 int strcmp(const char* _Nonnull __lhs, const char* _Nonnull __rhs) __attribute_pure__;
-char* _Nonnull stpcpy(char* _Nonnull __dst, const char* _Nonnull __src) __INTRODUCED_IN(21);
+char* _Nonnull stpcpy(char* _Nonnull __dst, const char* _Nonnull __src);
 char* _Nonnull strcpy(char* _Nonnull __dst, const char* _Nonnull __src);
 char* _Nonnull strcat(char* _Nonnull __dst, const char* _Nonnull __src);
 char* _Nullable strdup(const char* _Nonnull __s);
@@ -120,7 +120,7 @@
 char* _Nonnull strncat(char* _Nonnull __dst, const char* _Nonnull __src, size_t __n);
 char* _Nullable strndup(const char* _Nonnull __s, size_t __n);
 int strncmp(const char* _Nonnull __lhs, const char* _Nonnull __rhs, size_t __n) __attribute_pure__;
-char* _Nonnull stpncpy(char* _Nonnull __dst, const char* _Nonnull __src, size_t __n) __INTRODUCED_IN(21);
+char* _Nonnull stpncpy(char* _Nonnull __dst, const char* _Nonnull __src, size_t __n);
 char* _Nonnull strncpy(char* _Nonnull __dst, const char* _Nonnull __src, size_t __n);
 
 size_t strlcat(char* _Nonnull __dst, const char* _Nonnull __src, size_t __n);
@@ -136,8 +136,8 @@
 int strcoll(const char* _Nonnull __lhs, const char* _Nonnull __rhs) __attribute_pure__;
 size_t strxfrm(char* __BIONIC_COMPLICATED_NULLNESS __dst, const char* _Nonnull __src, size_t __n);
 
-int strcoll_l(const char* _Nonnull __lhs, const char* _Nonnull __rhs, locale_t _Nonnull __l) __attribute_pure__ __INTRODUCED_IN(21);
-size_t strxfrm_l(char* __BIONIC_COMPLICATED_NULLNESS __dst, const char* _Nonnull __src, size_t __n, locale_t _Nonnull __l) __INTRODUCED_IN(21);
+int strcoll_l(const char* _Nonnull __lhs, const char* _Nonnull __rhs, locale_t _Nonnull __l) __attribute_pure__;
+size_t strxfrm_l(char* __BIONIC_COMPLICATED_NULLNESS __dst, const char* _Nonnull __src, size_t __n, locale_t _Nonnull __l);
 
 #if defined(__USE_GNU) && !defined(basename)
 /*
diff --git a/libc/include/sys/auxv.h b/libc/include/sys/auxv.h
index bf70dda..b664e2a 100644
--- a/libc/include/sys/auxv.h
+++ b/libc/include/sys/auxv.h
@@ -45,9 +45,7 @@
  *
  * Returns the corresponding value on success,
  * and returns 0 and sets `errno` to `ENOENT` on failure.
- *
- * Available since API level 18.
  */
-unsigned long int getauxval(unsigned long int __type) __INTRODUCED_IN(18);
+unsigned long int getauxval(unsigned long int __type);
 
 __END_DECLS
diff --git a/libc/include/sys/endian.h b/libc/include/sys/endian.h
index 9155b4c..1c7448c 100644
--- a/libc/include/sys/endian.h
+++ b/libc/include/sys/endian.h
@@ -49,10 +49,10 @@
 
 /* glibc compatibility. */
 __BEGIN_DECLS
-uint32_t htonl(uint32_t __x) __attribute_const__ __INTRODUCED_IN(21);
-uint16_t htons(uint16_t __x) __attribute_const__ __INTRODUCED_IN(21);
-uint32_t ntohl(uint32_t __x) __attribute_const__ __INTRODUCED_IN(21);
-uint16_t ntohs(uint16_t __x) __attribute_const__ __INTRODUCED_IN(21);
+uint32_t htonl(uint32_t __x) __attribute_const__;
+uint16_t htons(uint16_t __x) __attribute_const__;
+uint32_t ntohl(uint32_t __x) __attribute_const__;
+uint16_t ntohs(uint16_t __x) __attribute_const__;
 __END_DECLS
 
 #define htonl(x) __swap32(x)
diff --git a/libc/include/sys/epoll.h b/libc/include/sys/epoll.h
index 9e09408..2091b90 100644
--- a/libc/include/sys/epoll.h
+++ b/libc/include/sys/epoll.h
@@ -38,11 +38,11 @@
 __BEGIN_DECLS
 
 int epoll_create(int __size);
-int epoll_create1(int __flags) __INTRODUCED_IN(21);
+int epoll_create1(int __flags);
 
 int epoll_ctl(int __epoll_fd, int __op, int __fd, struct epoll_event* __BIONIC_COMPLICATED_NULLNESS __event);
 int epoll_wait(int __epoll_fd, struct epoll_event* _Nonnull __events, int __event_count, int __timeout_ms);
-int epoll_pwait(int __epoll_fd, struct epoll_event* _Nonnull __events, int __event_count, int __timeout_ms, const sigset_t* _Nullable __mask) __INTRODUCED_IN(21);
+int epoll_pwait(int __epoll_fd, struct epoll_event* _Nonnull __events, int __event_count, int __timeout_ms, const sigset_t* _Nullable __mask);
 int epoll_pwait64(int __epoll_fd, struct epoll_event* _Nonnull __events, int __event_count, int __timeout_ms, const sigset64_t* _Nullable __mask) __INTRODUCED_IN(28);
 
 __END_DECLS
diff --git a/libc/include/sys/fsuid.h b/libc/include/sys/fsuid.h
index c1c8ebb..273749f 100644
--- a/libc/include/sys/fsuid.h
+++ b/libc/include/sys/fsuid.h
@@ -43,19 +43,15 @@
  * filesystem checks.
  *
  * Returns the previous UID.
- *
- * Available since API level 21.
  */
-int setfsuid(uid_t __uid) __INTRODUCED_IN(21);
+int setfsuid(uid_t __uid);
 
 /**
  * [setfsgid(2)](http://man7.org/linux/man-pages/man2/setfsgid.2.html) sets the GID used for
  * filesystem checks.
  *
  * Returns the previous GID.
- *
- * Available since API level 21.
  */
-int setfsgid(gid_t __gid) __INTRODUCED_IN(21);
+int setfsgid(gid_t __gid);
 
 __END_DECLS
diff --git a/libc/include/sys/inotify.h b/libc/include/sys/inotify.h
index e834d07..f070857 100644
--- a/libc/include/sys/inotify.h
+++ b/libc/include/sys/inotify.h
@@ -41,7 +41,7 @@
 #define IN_NONBLOCK O_NONBLOCK
 
 int inotify_init(void);
-int inotify_init1(int __flags) __INTRODUCED_IN(21);
+int inotify_init1(int __flags);
 int inotify_add_watch(int __fd, const char* _Nonnull __path, uint32_t __mask);
 int inotify_rm_watch(int __fd, uint32_t __watch_descriptor);
 
diff --git a/libc/include/sys/mman.h b/libc/include/sys/mman.h
index cbe6a75..f32ae61 100644
--- a/libc/include/sys/mman.h
+++ b/libc/include/sys/mman.h
@@ -59,10 +59,8 @@
  * mmap64() is a variant of mmap() that takes a 64-bit offset even on LP32.
  *
  * See https://android.googlesource.com/platform/bionic/+/master/docs/32-bit-abi.md
- *
- * Available since API level 21.
  */
-void* _Nonnull mmap64(void* _Nullable __addr, size_t __size, int __prot, int __flags, int __fd, off64_t __offset) __INTRODUCED_IN(21);
+void* _Nonnull mmap64(void* _Nullable __addr, size_t __size, int __prot, int __flags, int __fd, off64_t __offset);
 
 /**
  * [munmap(2)](http://man7.org/linux/man-pages/man2/munmap.2.html)
@@ -107,21 +105,17 @@
  * [mlockall(2)](http://man7.org/linux/man-pages/man2/mlockall.2.html)
  * locks pages (preventing swapping).
  *
- * Available since API level 17.
- *
  * Returns 0 on success, and returns -1 and sets `errno` on failure.
  */
-int mlockall(int __flags) __INTRODUCED_IN(17);
+int mlockall(int __flags);
 
 /**
  * [munlockall(2)](http://man7.org/linux/man-pages/man2/munlockall.2.html)
  * unlocks pages (allowing swapping).
  *
- * Available since API level 17.
- *
  * Returns 0 on success, and returns -1 and sets `errno` on failure.
  */
-int munlockall(void) __INTRODUCED_IN(17);
+int munlockall(void);
 
 /**
  * [mlock(2)](http://man7.org/linux/man-pages/man2/mlock.2.html)
diff --git a/libc/include/sys/resource.h b/libc/include/sys/resource.h
index 0b540de..6743343 100644
--- a/libc/include/sys/resource.h
+++ b/libc/include/sys/resource.h
@@ -46,8 +46,8 @@
 int getrlimit(int __resource, struct rlimit* _Nonnull __limit);
 int setrlimit(int __resource, const struct rlimit* _Nonnull __limit);
 
-int getrlimit64(int __resource, struct rlimit64* _Nonnull __limit) __INTRODUCED_IN(21);
-int setrlimit64(int __resource, const struct rlimit64* _Nonnull __limit) __INTRODUCED_IN(21);
+int getrlimit64(int __resource, struct rlimit64* _Nonnull __limit);
+int setrlimit64(int __resource, const struct rlimit64* _Nonnull __limit);
 
 int getpriority(int __which, id_t __who);
 int setpriority(int __which, id_t __who, int __priority);
@@ -55,7 +55,7 @@
 int getrusage(int __who, struct rusage* _Nonnull __usage);
 
 int prlimit(pid_t __pid, int __resource, const struct rlimit* _Nullable __new_limit, struct rlimit* _Nullable __old_limit) __INTRODUCED_IN_32(24) __INTRODUCED_IN_64(21);
-int prlimit64(pid_t __pid, int __resource, const struct rlimit64* _Nullable __new_limit, struct rlimit64* _Nullable __old_limit) __INTRODUCED_IN(21);
+int prlimit64(pid_t __pid, int __resource, const struct rlimit64* _Nullable __new_limit, struct rlimit64* _Nullable __old_limit);
 
 __END_DECLS
 
diff --git a/libc/include/sys/select.h b/libc/include/sys/select.h
index 8c6c2ff..84c2621 100644
--- a/libc/include/sys/select.h
+++ b/libc/include/sys/select.h
@@ -71,9 +71,9 @@
     } \
   } while (0)
 
-void __FD_CLR_chk(int, fd_set* _Nonnull , size_t) __INTRODUCED_IN(21);
-void __FD_SET_chk(int, fd_set* _Nonnull, size_t) __INTRODUCED_IN(21);
-int __FD_ISSET_chk(int, const fd_set* _Nonnull, size_t) __INTRODUCED_IN(21);
+void __FD_CLR_chk(int, fd_set* _Nonnull , size_t);
+void __FD_SET_chk(int, fd_set* _Nonnull, size_t);
+int __FD_ISSET_chk(int, const fd_set* _Nonnull, size_t);
 
 #define __FD_CLR(fd, set) (__FDS_BITS(fd_set*,set)[__FDELT(fd)] &= ~__FDMASK(fd))
 #define __FD_SET(fd, set) (__FDS_BITS(fd_set*,set)[__FDELT(fd)] |= __FDMASK(fd))
diff --git a/libc/include/sys/sendfile.h b/libc/include/sys/sendfile.h
index 4b00d5d..e1a34d2 100644
--- a/libc/include/sys/sendfile.h
+++ b/libc/include/sys/sendfile.h
@@ -40,15 +40,13 @@
 
 /* See https://android.googlesource.com/platform/bionic/+/master/docs/32-bit-abi.md */
 #if defined(__USE_FILE_OFFSET64)
-ssize_t sendfile(int __out_fd, int __in_fd, off_t* _Nullable __offset, size_t __count) __RENAME(sendfile64) __INTRODUCED_IN(21);
+ssize_t sendfile(int __out_fd, int __in_fd, off_t* _Nullable __offset, size_t __count) __RENAME(sendfile64);
 #else
 /**
  * [sendfile(2)](http://man7.org/linux/man-pages/man2/sendfile.2.html) copies data directly
  * between two file descriptors.
  *
  * Returns the number of bytes copied on success, and returns -1 and sets `errno` on failure.
- *
- * Available since API level 21.
  */
 ssize_t sendfile(int __out_fd, int __in_fd, off_t* _Nullable __offset, size_t __count);
 #endif
@@ -57,6 +55,6 @@
  * Like sendfile() but allows using a 64-bit offset
  * even from a 32-bit process without `__FILE_OFFSET_BITS=64`.
  */
-ssize_t sendfile64(int __out_fd, int __in_fd, off64_t* _Nullable __offset, size_t __count) __INTRODUCED_IN(21);
+ssize_t sendfile64(int __out_fd, int __in_fd, off64_t* _Nullable __offset, size_t __count);
 
 __END_DECLS
diff --git a/libc/include/sys/signalfd.h b/libc/include/sys/signalfd.h
index f669cc8..2be9bdc 100644
--- a/libc/include/sys/signalfd.h
+++ b/libc/include/sys/signalfd.h
@@ -45,10 +45,8 @@
  * file descriptor for reading signal events.
  *
  * Returns the file descriptor on success, and returns -1 and sets `errno` on failure.
- *
- * Available since API level 18.
  */
-int signalfd(int __fd, const sigset_t* _Nonnull __mask, int __flags) __INTRODUCED_IN(18);
+int signalfd(int __fd, const sigset_t* _Nonnull __mask, int __flags);
 
 /**
  * Like signalfd() but allows setting a signal mask with RT signals even from a 32-bit process.
diff --git a/libc/include/sys/socket.h b/libc/include/sys/socket.h
index 821c483..22b88cb 100644
--- a/libc/include/sys/socket.h
+++ b/libc/include/sys/socket.h
@@ -120,7 +120,7 @@
    ? (struct cmsghdr*) (msg)->msg_control : (struct cmsghdr*) NULL)
 #define CMSG_OK(mhdr, cmsg) ((cmsg)->cmsg_len >= sizeof(struct cmsghdr) &&   (cmsg)->cmsg_len <= (unsigned long)   ((mhdr)->msg_controllen -   ((char*)(cmsg) - (char*)(mhdr)->msg_control)))
 
-struct cmsghdr* _Nullable __cmsg_nxthdr(struct msghdr* _Nonnull __msg, struct cmsghdr* _Nonnull __cmsg) __INTRODUCED_IN(21);
+struct cmsghdr* _Nullable __cmsg_nxthdr(struct msghdr* _Nonnull __msg, struct cmsghdr* _Nonnull __cmsg);
 
 #define SCM_RIGHTS 0x01
 #define SCM_CREDENTIALS 0x02
@@ -292,17 +292,16 @@
 #endif
 
 __socketcall int accept(int __fd, struct sockaddr* _Nullable __addr, socklen_t* _Nullable __addr_length);
-__socketcall int accept4(int __fd, struct sockaddr* _Nullable __addr, socklen_t* _Nullable __addr_length, int __flags) __INTRODUCED_IN(21);
+__socketcall int accept4(int __fd, struct sockaddr* _Nullable __addr, socklen_t* _Nullable __addr_length, int __flags);
 __socketcall int bind(int __fd, const struct sockaddr* _Nonnull __addr, socklen_t __addr_length);
 __socketcall int connect(int __fd, const struct sockaddr* _Nonnull __addr, socklen_t __addr_length);
 __socketcall int getpeername(int __fd, struct sockaddr* _Nonnull __addr, socklen_t* _Nonnull __addr_length);
 __socketcall int getsockname(int __fd, struct sockaddr* _Nonnull __addr, socklen_t* _Nonnull __addr_length);
 __socketcall int getsockopt(int __fd, int __level, int __option, void* _Nullable __value, socklen_t* _Nonnull __value_length);
 __socketcall int listen(int __fd, int __backlog);
-__socketcall int recvmmsg(int __fd, struct mmsghdr* _Nonnull __msgs, unsigned int __msg_count, int __flags, const struct timespec* _Nullable __timeout)
-  __INTRODUCED_IN(21);
+__socketcall int recvmmsg(int __fd, struct mmsghdr* _Nonnull __msgs, unsigned int __msg_count, int __flags, const struct timespec* _Nullable __timeout);
 __socketcall ssize_t recvmsg(int __fd, struct msghdr* _Nonnull __msg, int __flags);
-__socketcall int sendmmsg(int __fd, const struct mmsghdr* _Nonnull __msgs, unsigned int __msg_count, int __flags) __INTRODUCED_IN(21);
+__socketcall int sendmmsg(int __fd, const struct mmsghdr* _Nonnull __msgs, unsigned int __msg_count, int __flags);
 __socketcall ssize_t sendmsg(int __fd, const struct msghdr* _Nonnull __msg, int __flags);
 __socketcall int setsockopt(int __fd, int __level, int __option, const void* _Nullable __value, socklen_t __value_length);
 __socketcall int shutdown(int __fd, int __how);
diff --git a/libc/include/sys/stat.h b/libc/include/sys/stat.h
index f773ff6..f916573 100644
--- a/libc/include/sys/stat.h
+++ b/libc/include/sys/stat.h
@@ -141,13 +141,13 @@
 int mkdir(const char* _Nonnull __path, mode_t __mode);
 
 int fstat(int __fd, struct stat* _Nonnull __buf);
-int fstat64(int __fd, struct stat64* _Nonnull __buf) __INTRODUCED_IN(21);
+int fstat64(int __fd, struct stat64* _Nonnull __buf);
 int fstatat(int __dir_fd, const char* _Nonnull __path, struct stat* _Nonnull __buf, int __flags);
-int fstatat64(int __dir_fd, const char* _Nonnull __path, struct stat64* _Nonnull __buf, int __flags) __INTRODUCED_IN(21);
+int fstatat64(int __dir_fd, const char* _Nonnull __path, struct stat64* _Nonnull __buf, int __flags);
 int lstat(const char* _Nonnull __path, struct stat* _Nonnull __buf);
-int lstat64(const char* _Nonnull __path, struct stat64* _Nonnull __buf) __INTRODUCED_IN(21);
+int lstat64(const char* _Nonnull __path, struct stat64* _Nonnull __buf);
 int stat(const char* _Nonnull __path, struct stat* _Nonnull __buf);
-int stat64(const char* _Nonnull __path, struct stat64* _Nonnull __buf) __INTRODUCED_IN(21);
+int stat64(const char* _Nonnull __path, struct stat64* _Nonnull __buf);
 
 int mknod(const char* _Nonnull __path, mode_t __mode, dev_t __dev);
 mode_t umask(mode_t __mask);
@@ -156,12 +156,12 @@
 #include <bits/fortify/stat.h>
 #endif
 
-int mkfifo(const char* _Nonnull __path, mode_t __mode) __INTRODUCED_IN(21);
+int mkfifo(const char* _Nonnull __path, mode_t __mode);
 int mkfifoat(int __dir_fd, const char* _Nonnull __path, mode_t __mode) __INTRODUCED_IN(23);
 
 int fchmodat(int __dir_fd, const char* _Nonnull __path, mode_t __mode, int __flags);
 int mkdirat(int __dir_fd, const char* _Nonnull __path, mode_t __mode);
-int mknodat(int __dir_fd, const char* _Nonnull __path, mode_t __mode, dev_t __dev) __INTRODUCED_IN(21);
+int mknodat(int __dir_fd, const char* _Nonnull __path, mode_t __mode, dev_t __dev);
 
 /**
  * Used in the tv_nsec field of an argument to utimensat()/futimens()
@@ -200,10 +200,8 @@
  * See also UTIME_NOW and UTIME_OMIT.
  *
  * Returns 0 on success and returns -1 and sets `errno` on failure.
- *
- * Available since API level 19.
  */
-int futimens(int __fd, const struct timespec __times[_Nullable 2]) __INTRODUCED_IN(19);
+int futimens(int __fd, const struct timespec __times[_Nullable 2]);
 
 #if defined(__USE_GNU)
 /**
diff --git a/libc/include/sys/statvfs.h b/libc/include/sys/statvfs.h
index d81f836..46fbea5 100644
--- a/libc/include/sys/statvfs.h
+++ b/libc/include/sys/statvfs.h
@@ -93,25 +93,21 @@
  * queries filesystem statistics for the given path.
  *
  * Returns 0 on success, and returns -1 and sets `errno` on failure.
- *
- * Available since API level 19.
  */
-int statvfs(const char* _Nonnull __path, struct statvfs* _Nonnull __buf) __INTRODUCED_IN(19);
+int statvfs(const char* _Nonnull __path, struct statvfs* _Nonnull __buf);
 
 /**
  * [fstatvfs(3)](http://man7.org/linux/man-pages/man3/fstatvfs.3.html)
  * queries filesystem statistics for the given file descriptor.
  *
  * Returns 0 on success, and returns -1 and sets `errno` on failure.
- *
- * Available since API level 19.
  */
-int fstatvfs(int __fd, struct statvfs* _Nonnull __buf) __INTRODUCED_IN(19);
+int fstatvfs(int __fd, struct statvfs* _Nonnull __buf);
 
 /** Equivalent to statvfs() . */
-int statvfs64(const char* _Nonnull __path, struct statvfs64* _Nonnull __buf) __INTRODUCED_IN(21);
+int statvfs64(const char* _Nonnull __path, struct statvfs64* _Nonnull __buf);
 
 /** Equivalent to fstatvfs(). */
-int fstatvfs64(int __fd, struct statvfs64* _Nonnull __buf) __INTRODUCED_IN(21);
+int fstatvfs64(int __fd, struct statvfs64* _Nonnull __buf);
 
 __END_DECLS
diff --git a/libc/include/sys/swap.h b/libc/include/sys/swap.h
index 9d016d4..474aed7 100644
--- a/libc/include/sys/swap.h
+++ b/libc/include/sys/swap.h
@@ -55,18 +55,14 @@
  * [swapon(2)](http://man7.org/linux/man-pages/man2/swapon.2.html) enables swapping.
  *
  * Returns 0 on success, and returns -1 and sets `errno` on failure.
- *
- * Available since API level 19.
  */
-int swapon(const char* _Nonnull __path,  int __flags) __INTRODUCED_IN(19);
+int swapon(const char* _Nonnull __path,  int __flags);
 
 /**
  * [swapoff(2)](http://man7.org/linux/man-pages/man2/swapoff.2.html) disables swapping.
  *
  * Returns 0 on success, and returns -1 and sets `errno` on failure.
- *
- * Available since API level 19.
  */
-int swapoff(const char* _Nonnull __path) __INTRODUCED_IN(19);
+int swapoff(const char* _Nonnull __path);
 
 __END_DECLS
diff --git a/libc/include/sys/system_properties.h b/libc/include/sys/system_properties.h
index 06b2188..dc869da 100644
--- a/libc/include/sys/system_properties.h
+++ b/libc/include/sys/system_properties.h
@@ -66,8 +66,7 @@
  *
  * This method is for inspecting and debugging the property system, and not generally useful.
  */
-int __system_property_foreach(void (* _Nonnull __callback)(const prop_info* _Nonnull __pi, void* _Nullable __cookie), void* _Nullable __cookie)
-  __INTRODUCED_IN(19);
+int __system_property_foreach(void (* _Nonnull __callback)(const prop_info* _Nonnull __pi, void* _Nullable __cookie), void* _Nullable __cookie);
 
 /*
  * Waits for the specific system property identified by `pi` to be updated
diff --git a/libc/include/sys/timerfd.h b/libc/include/sys/timerfd.h
index aafcef2..de1f55b 100644
--- a/libc/include/sys/timerfd.h
+++ b/libc/include/sys/timerfd.h
@@ -50,10 +50,8 @@
  * timer file descriptor.
  *
  * Returns the new file descriptor on success, and returns -1 and sets `errno` on failure.
- *
- * Available since API level 19.
  */
-int timerfd_create(clockid_t __clock, int __flags) __INTRODUCED_IN(19);
+int timerfd_create(clockid_t __clock, int __flags);
 
 /** The timerfd_settime() flag to use absolute rather than relative times. */
 #define TFD_TIMER_ABSTIME (1 << 0)
@@ -65,19 +63,15 @@
  * stops a timer.
  *
  * Returns 0 on success, and returns -1 and sets `errno` on failure.
- *
- * Available since API level 19.
  */
-int timerfd_settime(int __fd, int __flags, const struct itimerspec* _Nonnull __new_value, struct itimerspec* _Nullable __old_value) __INTRODUCED_IN(19);
+int timerfd_settime(int __fd, int __flags, const struct itimerspec* _Nonnull __new_value, struct itimerspec* _Nullable __old_value);
 
 /**
  * [timerfd_gettime(2)](http://man7.org/linux/man-pages/man2/timerfd_gettime.2.html) queries the
  * current timer settings.
  *
  * Returns 0 on success, and returns -1 and sets `errno` on failure.
- *
- * Available since API level 19.
  */
-int timerfd_gettime(int __fd, struct itimerspec* _Nonnull __current_value) __INTRODUCED_IN(19);
+int timerfd_gettime(int __fd, struct itimerspec* _Nonnull __current_value);
 
 __END_DECLS
diff --git a/libc/include/sys/vfs.h b/libc/include/sys/vfs.h
index 18ae428..3579799 100644
--- a/libc/include/sys/vfs.h
+++ b/libc/include/sys/vfs.h
@@ -105,9 +105,9 @@
 #define XFS_SUPER_MAGIC       0x58465342
 
 int statfs(const char* _Nonnull __path, struct statfs* _Nonnull __buf);
-int statfs64(const char* _Nonnull __path, struct statfs64* _Nonnull __buf) __INTRODUCED_IN(21);
+int statfs64(const char* _Nonnull __path, struct statfs64* _Nonnull __buf);
 int fstatfs(int __fd, struct statfs* _Nonnull __buf);
-int fstatfs64(int __fd, struct statfs64* _Nonnull __buf) __INTRODUCED_IN(21);
+int fstatfs64(int __fd, struct statfs64* _Nonnull __buf);
 
 __END_DECLS
 
diff --git a/libc/include/sys/wait.h b/libc/include/sys/wait.h
index e6fb855..5208366 100644
--- a/libc/include/sys/wait.h
+++ b/libc/include/sys/wait.h
@@ -39,7 +39,7 @@
 
 pid_t wait(int* _Nullable __status);
 pid_t waitpid(pid_t __pid, int* _Nullable __status, int __options);
-pid_t wait4(pid_t __pid, int* _Nullable __status, int __options, struct rusage* _Nullable __rusage) __INTRODUCED_IN(18);
+pid_t wait4(pid_t __pid, int* _Nullable __status, int __options, struct rusage* _Nullable __rusage);
 
 /* Posix states that idtype_t should be an enumeration type, but
  * the kernel headers define P_ALL, P_PID and P_PGID as constant macros
diff --git a/libc/include/termios.h b/libc/include/termios.h
index 92ac24b..853b4eb 100644
--- a/libc/include/termios.h
+++ b/libc/include/termios.h
@@ -49,19 +49,19 @@
  * [cfgetispeed(3)](http://man7.org/linux/man-pages/man3/cfgetispeed.3.html)
  * returns the terminal input baud rate.
  */
-speed_t cfgetispeed(const struct termios* _Nonnull __t) __INTRODUCED_IN(21);
+speed_t cfgetispeed(const struct termios* _Nonnull __t);
 
 /**
  * [cfgetospeed(3)](http://man7.org/linux/man-pages/man3/cfgetospeed.3.html)
  * returns the terminal output baud rate.
  */
-speed_t cfgetospeed(const struct termios* _Nonnull __t) __INTRODUCED_IN(21);
+speed_t cfgetospeed(const struct termios* _Nonnull __t);
 
 /**
  * [cfmakeraw(3)](http://man7.org/linux/man-pages/man3/cfmakeraw.3.html)
  * configures the terminal for "raw" mode.
  */
-void cfmakeraw(struct termios* _Nonnull __t) __INTRODUCED_IN(21);
+void cfmakeraw(struct termios* _Nonnull __t);
 
 /**
  * [cfsetspeed(3)](http://man7.org/linux/man-pages/man3/cfsetspeed.3.html)
@@ -69,7 +69,7 @@
  *
  * Returns 0 on success and returns -1 and sets `errno` on failure.
  */
-int cfsetspeed(struct termios* _Nonnull __t, speed_t __speed) __INTRODUCED_IN(21);
+int cfsetspeed(struct termios* _Nonnull __t, speed_t __speed);
 
 /**
  * [cfsetispeed(3)](http://man7.org/linux/man-pages/man3/cfsetispeed.3.html)
@@ -77,7 +77,7 @@
  *
  * Returns 0 on success and returns -1 and sets `errno` on failure.
  */
-int cfsetispeed(struct termios* _Nonnull _t, speed_t __speed) __INTRODUCED_IN(21);
+int cfsetispeed(struct termios* _Nonnull _t, speed_t __speed);
 
 /**
  * [cfsetospeed(3)](http://man7.org/linux/man-pages/man3/cfsetospeed.3.html)
@@ -85,7 +85,7 @@
  *
  * Returns 0 on success and returns -1 and sets `errno` on failure.
  */
-int cfsetospeed(struct termios* _Nonnull __t, speed_t __speed) __INTRODUCED_IN(21);
+int cfsetospeed(struct termios* _Nonnull __t, speed_t __speed);
 
 /**
  * [tcdrain(3)](http://man7.org/linux/man-pages/man3/tcdrain.3.html)
@@ -93,7 +93,7 @@
  *
  * Returns 0 on success and returns -1 and sets `errno` on failure.
  */
-int tcdrain(int __fd) __INTRODUCED_IN(21);
+int tcdrain(int __fd);
 
 /**
  * [tcflow(3)](http://man7.org/linux/man-pages/man3/tcflow.3.html)
@@ -102,7 +102,7 @@
  *
  * Returns 0 on success and returns -1 and sets `errno` on failure.
  */
-int tcflow(int __fd, int __action) __INTRODUCED_IN(21);
+int tcflow(int __fd, int __action);
 
 /**
  * [tcflush(3)](http://man7.org/linux/man-pages/man3/tcflush.3.html)
@@ -112,7 +112,7 @@
  *
  * Returns 0 on success and returns -1 and sets `errno` on failure.
  */
-int tcflush(int __fd, int __queue) __INTRODUCED_IN(21);
+int tcflush(int __fd, int __queue);
 
 /**
  * [tcgetattr(3)](http://man7.org/linux/man-pages/man3/tcgetattr.3.html)
@@ -120,7 +120,7 @@
  *
  * Returns 0 on success and returns -1 and sets `errno` on failure.
  */
-int tcgetattr(int __fd, struct termios* _Nonnull __t) __INTRODUCED_IN(21);
+int tcgetattr(int __fd, struct termios* _Nonnull __t);
 
 /**
  * [tcgetsid(3)](http://man7.org/linux/man-pages/man3/tcgetsid.3.html)
@@ -129,7 +129,7 @@
  * Returns a non-negative session id on success and
  * returns -1 and sets `errno` on failure.
  */
-pid_t tcgetsid(int __fd) __INTRODUCED_IN(21);
+pid_t tcgetsid(int __fd);
 
 /**
  * [tcsendbreak(3)](http://man7.org/linux/man-pages/man3/tcsendbreak.3.html)
@@ -137,7 +137,7 @@
  *
  * Returns 0 on success and returns -1 and sets `errno` on failure.
  */
-int tcsendbreak(int __fd, int __duration) __INTRODUCED_IN(21);
+int tcsendbreak(int __fd, int __duration);
 
 /**
  * [tcsetattr(3)](http://man7.org/linux/man-pages/man3/tcsetattr.3.html)
@@ -145,7 +145,7 @@
  *
  * Returns 0 on success and returns -1 and sets `errno` on failure.
  */
-int tcsetattr(int __fd, int __optional_actions, const struct termios* _Nonnull __t) __INTRODUCED_IN(21);
+int tcsetattr(int __fd, int __optional_actions, const struct termios* _Nonnull __t);
 
 #endif
 
diff --git a/libc/include/time.h b/libc/include/time.h
index bd3fac1..5b76288 100644
--- a/libc/include/time.h
+++ b/libc/include/time.h
@@ -252,7 +252,7 @@
 /**
  * Equivalent to strftime() on Android where only C/POSIX locales are available.
  */
-size_t strftime_l(char* _Nonnull __buf, size_t __n, const char* _Nonnull __fmt, const struct tm* _Nullable __tm, locale_t _Nonnull __l) __strftimelike(3) __INTRODUCED_IN(21);
+size_t strftime_l(char* _Nonnull __buf, size_t __n, const char* _Nonnull __fmt, const struct tm* _Nullable __tm, locale_t _Nonnull __l) __strftimelike(3);
 
 /**
  * [ctime(3)](http://man7.org/linux/man-pages/man3/ctime.3p.html) formats
diff --git a/libc/include/uchar.h b/libc/include/uchar.h
index 90af651..0c7424d 100644
--- a/libc/include/uchar.h
+++ b/libc/include/uchar.h
@@ -58,10 +58,8 @@
  *
  * Returns the number of bytes written to `__buf` on success, and returns -1 and sets `errno`
  * on failure.
- *
- * Available since API level 21.
  */
-size_t c16rtomb(char* _Nullable __buf, char16_t __ch16, mbstate_t* _Nullable __ps) __INTRODUCED_IN(21);
+size_t c16rtomb(char* _Nullable __buf, char16_t __ch16, mbstate_t* _Nullable __ps);
 
 /**
  * [c32rtomb(3)](http://man7.org/linux/man-pages/man3/c32rtomb.3.html) converts a single UTF-32
@@ -69,25 +67,19 @@
  *
  * Returns the number of bytes written to `__buf` on success, and returns -1 and sets `errno`
  * on failure.
- *
- * Available since API level 21.
  */
-size_t c32rtomb(char* _Nullable __buf, char32_t __ch32, mbstate_t* _Nullable __ps) __INTRODUCED_IN(21);
+size_t c32rtomb(char* _Nullable __buf, char32_t __ch32, mbstate_t* _Nullable __ps);
 
 /**
  * [mbrtoc16(3)](http://man7.org/linux/man-pages/man3/mbrtoc16.3.html) converts the next UTF-8
  * sequence to a UTF-16 code point.
- *
- * Available since API level 21.
  */
-size_t mbrtoc16(char16_t* _Nullable __ch16, const char* _Nullable __s, size_t __n, mbstate_t* _Nullable __ps) __INTRODUCED_IN(21);
+size_t mbrtoc16(char16_t* _Nullable __ch16, const char* _Nullable __s, size_t __n, mbstate_t* _Nullable __ps);
 
 /**
  * [mbrtoc32(3)](http://man7.org/linux/man-pages/man3/mbrtoc32.3.html) converts the next UTF-8
  * sequence to a UTF-32 code point.
- *
- * Available since API level 21.
  */
-size_t mbrtoc32(char32_t* _Nullable __ch32, const char* _Nullable __s, size_t __n, mbstate_t* _Nullable __ps) __INTRODUCED_IN(21);
+size_t mbrtoc32(char32_t* _Nullable __ch32, const char* _Nullable __s, size_t __n, mbstate_t* _Nullable __ps);
 
 __END_DECLS
diff --git a/libc/include/unistd.h b/libc/include/unistd.h
index 7ad94e1..98fab52 100644
--- a/libc/include/unistd.h
+++ b/libc/include/unistd.h
@@ -86,12 +86,12 @@
 pid_t  getppid(void);
 pid_t  getpgrp(void);
 int    setpgrp(void);
-pid_t  getsid(pid_t __pid) __INTRODUCED_IN(17);
+pid_t  getsid(pid_t __pid);
 pid_t  setsid(void);
 
 int execv(const char* _Nonnull __path, char* _Nullable const* _Nullable __argv);
 int execvp(const char* _Nonnull __file, char* _Nullable const* _Nullable __argv);
-int execvpe(const char* _Nonnull __file, char* _Nullable const* _Nullable __argv, char* _Nullable const* _Nullable __envp) __INTRODUCED_IN(21);
+int execvpe(const char* _Nonnull __file, char* _Nullable const* _Nullable __argv, char* _Nullable const* _Nullable __envp);
 int execve(const char* _Nonnull __file, char* _Nullable const* _Nullable __argv, char* _Nullable const* _Nullable __envp);
 int execl(const char* _Nonnull __path, const char* _Nullable __arg0, ...) __attribute__((__sentinel__));
 int execlp(const char* _Nonnull __file, const char* _Nullable __arg0, ...) __attribute__((__sentinel__));
@@ -206,7 +206,7 @@
 int access(const char* _Nonnull __path, int __mode);
 int faccessat(int __dirfd, const char* _Nonnull __path, int __mode, int __flags);
 int link(const char* _Nonnull __old_path, const char* _Nonnull __new_path);
-int linkat(int __old_dir_fd, const char* _Nonnull __old_path, int __new_dir_fd, const char* _Nonnull __new_path, int __flags) __INTRODUCED_IN(21);
+int linkat(int __old_dir_fd, const char* _Nonnull __old_path, int __new_dir_fd, const char* _Nonnull __new_path, int __flags);
 int unlink(const char* _Nonnull __path);
 int unlinkat(int __dirfd, const char* _Nonnull __path, int __flags);
 int chdir(const char* _Nonnull __path);
@@ -218,10 +218,9 @@
 #endif
 int chroot(const char* _Nonnull __path);
 int symlink(const char* _Nonnull __old_path, const char* _Nonnull __new_path);
-int symlinkat(const char* _Nonnull __old_path, int __new_dir_fd, const char* _Nonnull __new_path) __INTRODUCED_IN(21);
+int symlinkat(const char* _Nonnull __old_path, int __new_dir_fd, const char* _Nonnull __new_path);
 ssize_t readlink(const char* _Nonnull __path, char* _Nonnull __buf, size_t __buf_size);
-ssize_t readlinkat(int __dir_fd, const char* _Nonnull __path, char* _Nonnull __buf, size_t __buf_size)
-    __INTRODUCED_IN(21);
+ssize_t readlinkat(int __dir_fd, const char* _Nonnull __path, char* _Nonnull __buf, size_t __buf_size);
 int chown(const char* _Nonnull __path, uid_t __owner, gid_t __group);
 int fchown(int __fd, uid_t __owner, gid_t __group);
 int fchownat(int __dir_fd, const char* _Nonnull __path, uid_t __owner, gid_t __group, int __flags);
@@ -261,13 +260,13 @@
 
 int dup(int __old_fd);
 int dup2(int __old_fd, int __new_fd);
-int dup3(int __old_fd, int __new_fd, int __flags) __INTRODUCED_IN(21);
+int dup3(int __old_fd, int __new_fd, int __flags);
 int fsync(int __fd);
 int fdatasync(int __fd);
 
 /* See https://android.googlesource.com/platform/bionic/+/master/docs/32-bit-abi.md */
 #if defined(__USE_FILE_OFFSET64)
-int truncate(const char* _Nonnull __path, off_t __length) __RENAME(truncate64) __INTRODUCED_IN(21);
+int truncate(const char* _Nonnull __path, off_t __length) __RENAME(truncate64);
 off_t lseek(int __fd, off_t __offset, int __whence) __RENAME(lseek64);
 ssize_t pread(int __fd, void* _Nonnull __buf, size_t __count, off_t __offset) __RENAME(pread64);
 ssize_t pwrite(int __fd, const void* _Nonnull __buf, size_t __count, off_t __offset) __RENAME(pwrite64);
@@ -280,7 +279,7 @@
 int ftruncate(int __fd, off_t __length);
 #endif
 
-int truncate64(const char* _Nonnull __path, off64_t __length) __INTRODUCED_IN(21);
+int truncate64(const char* _Nonnull __path, off64_t __length);
 off64_t lseek64(int __fd, off64_t __offset, int __whence);
 ssize_t pread64(int __fd, void* _Nonnull __buf, size_t __count, off64_t __offset);
 ssize_t pwrite64(int __fd, const void* _Nonnull __buf, size_t __count, off64_t __offset);
@@ -303,7 +302,7 @@
 
 int acct(const char* _Nullable __path);
 
-int getpagesize(void) __INTRODUCED_IN(21);
+int getpagesize(void);
 
 long syscall(long __number, ...);
 
diff --git a/libc/include/wchar.h b/libc/include/wchar.h
index 1060d97..2671580 100644
--- a/libc/include/wchar.h
+++ b/libc/include/wchar.h
@@ -58,18 +58,18 @@
 size_t mbrtowc(wchar_t* _Nullable __buf, const char* _Nullable __s, size_t __n, mbstate_t* _Nullable __ps);
 size_t mbsrtowcs(wchar_t* _Nullable __dst, const char* _Nullable * _Nonnull __src, size_t __dst_n, mbstate_t* _Nullable __ps);
 size_t mbsrtowcs_l(wchar_t* _Nullable __dst, const char* _Nullable * _Nonnull __src, size_t __dst_n, mbstate_t* _Nullable __ps, locale_t _Nonnull __l) __INTRODUCED_IN(35);
-size_t mbsnrtowcs(wchar_t* _Nullable __dst, const char* _Nullable * _Nullable  __src, size_t __src_n, size_t __dst_n, mbstate_t* _Nullable __ps) __INTRODUCED_IN(21);
+size_t mbsnrtowcs(wchar_t* _Nullable __dst, const char* _Nullable * _Nullable  __src, size_t __src_n, size_t __dst_n, mbstate_t* _Nullable __ps);
 wint_t putwc(wchar_t __wc, FILE* _Nonnull __fp);
 wint_t putwchar(wchar_t __wc);
 int swprintf(wchar_t* _Nonnull __buf, size_t __n, const wchar_t* _Nonnull __fmt, ...);
 int swscanf(const wchar_t* _Nonnull __s, const wchar_t* _Nonnull __fmt, ...);
 wint_t ungetwc(wint_t __wc, FILE* _Nonnull __fp);
 int vfwprintf(FILE* _Nonnull __fp, const wchar_t* _Nonnull __fmt, va_list __args);
-int vfwscanf(FILE* _Nonnull __fp, const wchar_t* _Nonnull __fmt, va_list __args) __INTRODUCED_IN(21);
+int vfwscanf(FILE* _Nonnull __fp, const wchar_t* _Nonnull __fmt, va_list __args);
 int vswprintf(wchar_t* _Nonnull __buf, size_t __n, const wchar_t* _Nonnull __fmt, va_list __args);
-int vswscanf(const wchar_t* _Nonnull __s, const wchar_t* _Nonnull __fmt, va_list __args) __INTRODUCED_IN(21);
+int vswscanf(const wchar_t* _Nonnull __s, const wchar_t* _Nonnull __fmt, va_list __args);
 int vwprintf(const wchar_t* _Nonnull __fmt, va_list __args);
-int vwscanf(const wchar_t* _Nonnull __fmt, va_list __args) __INTRODUCED_IN(21);
+int vwscanf(const wchar_t* _Nonnull __fmt, va_list __args);
 wchar_t* _Nonnull wcpcpy(wchar_t* _Nonnull __dst, const wchar_t* _Nonnull __src);
 wchar_t* _Nonnull wcpncpy(wchar_t* _Nonnull __dst, const wchar_t* _Nonnull __src, size_t __n);
 size_t wcrtomb(char* _Nullable __buf, wchar_t __wc, mbstate_t* _Nullable __ps);
@@ -89,7 +89,7 @@
 wchar_t* _Nonnull wcsncat(wchar_t* _Nonnull __dst, const wchar_t* _Nonnull __src, size_t __n);
 int wcsncmp(const wchar_t* _Nonnull __lhs, const wchar_t* _Nonnull __rhs, size_t __n);
 wchar_t* _Nonnull wcsncpy(wchar_t* _Nonnull __dst, const wchar_t* _Nonnull __src, size_t __n);
-size_t wcsnrtombs(char* _Nullable __dst, const wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __src, size_t __src_n, size_t __dst_n, mbstate_t* _Nullable __ps) __INTRODUCED_IN(21);
+size_t wcsnrtombs(char* _Nullable __dst, const wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __src, size_t __src_n, size_t __dst_n, mbstate_t* _Nullable __ps);
 wchar_t* _Nullable wcspbrk(const wchar_t* _Nonnull __s, const wchar_t* _Nonnull __accept);
 wchar_t* _Nullable wcsrchr(const wchar_t* _Nonnull __s, wchar_t __wc);
 size_t wcsrtombs(char* _Nullable __dst, const wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __src, size_t __dst_n, mbstate_t* _Nullable __ps);
@@ -98,16 +98,16 @@
 wchar_t* _Nullable wcsstr(const wchar_t* _Nonnull __haystack, const wchar_t* _Nonnull __needle);
 double wcstod(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr);
 double wcstod_l(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr, locale_t _Nonnull __l) __INTRODUCED_IN(28);
-float wcstof(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr) __INTRODUCED_IN(21);
+float wcstof(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr);
 float wcstof_l(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr, locale_t _Nonnull __l) __INTRODUCED_IN(28);
 wchar_t* _Nullable wcstok(wchar_t* _Nullable __s, const wchar_t* _Nonnull __delimiter, wchar_t* _Nonnull * _Nonnull __ptr);
 long wcstol(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr, int __base);
 long wcstol_l(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr, int __base, locale_t _Nonnull __l) __INTRODUCED_IN(28);
-long long wcstoll(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr, int __base) __INTRODUCED_IN(21);
-long double wcstold(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr) __INTRODUCED_IN(21);
+long long wcstoll(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr, int __base);
+long double wcstold(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr);
 unsigned long wcstoul(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr, int __base);
 unsigned long wcstoul_l(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr, int __base, locale_t _Nonnull __l) __INTRODUCED_IN(28);
-unsigned long long wcstoull(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr, int __base) __INTRODUCED_IN(21);
+unsigned long long wcstoull(const wchar_t* _Nonnull __s, wchar_t* __BIONIC_COMPLICATED_NULLNESS * _Nullable __end_ptr, int __base);
 int wcswidth(const wchar_t* _Nonnull __s, size_t __n);
 size_t wcsxfrm(wchar_t* __BIONIC_COMPLICATED_NULLNESS __dst, const wchar_t* _Nonnull __src, size_t __n);
 int wctob(wint_t __wc);
@@ -123,13 +123,12 @@
 int wprintf(const wchar_t* _Nonnull __fmt, ...);
 int wscanf(const wchar_t* _Nonnull __fmt, ...);
 
-long long wcstoll_l(const wchar_t* _Nonnull __s, wchar_t* _Nullable * _Nullable __end_ptr, int __base, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-unsigned long long wcstoull_l(const wchar_t* _Nonnull __s, wchar_t* _Nullable * _Nullable __end_ptr, int __base, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-long double wcstold_l(const wchar_t* _Nonnull __s, wchar_t* _Nullable * _Nullable __end_ptr, locale_t _Nonnull __l) __INTRODUCED_IN(21);
+long long wcstoll_l(const wchar_t* _Nonnull __s, wchar_t* _Nullable * _Nullable __end_ptr, int __base, locale_t _Nonnull __l);
+unsigned long long wcstoull_l(const wchar_t* _Nonnull __s, wchar_t* _Nullable * _Nullable __end_ptr, int __base, locale_t _Nonnull __l);
+long double wcstold_l(const wchar_t* _Nonnull __s, wchar_t* _Nullable * _Nullable __end_ptr, locale_t _Nonnull __l);
 
-int wcscoll_l(const wchar_t* _Nonnull __lhs, const wchar_t* _Nonnull __rhs, locale_t _Nonnull __l) __attribute_pure__
-    __INTRODUCED_IN(21);
-size_t wcsxfrm_l(wchar_t* __BIONIC_COMPLICATED_NULLNESS __dst, const wchar_t* _Nonnull __src, size_t __n, locale_t _Nonnull __l) __INTRODUCED_IN(21);
+int wcscoll_l(const wchar_t* _Nonnull __lhs, const wchar_t* _Nonnull __rhs, locale_t _Nonnull __l) __attribute_pure__;
+size_t wcsxfrm_l(wchar_t* __BIONIC_COMPLICATED_NULLNESS __dst, const wchar_t* _Nonnull __src, size_t __n, locale_t _Nonnull __l);
 size_t wcslcat(wchar_t* _Nonnull __dst, const wchar_t* _Nonnull __src, size_t __n);
 size_t wcslcpy(wchar_t* _Nonnull __dst, const wchar_t* _Nonnull __src, size_t __n);
 
diff --git a/libc/include/wctype.h b/libc/include/wctype.h
index 344343f..4f6f81f 100644
--- a/libc/include/wctype.h
+++ b/libc/include/wctype.h
@@ -35,27 +35,27 @@
 
 __BEGIN_DECLS
 
-int iswalnum_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-int iswalpha_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-int iswblank_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-int iswcntrl_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-int iswdigit_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-int iswgraph_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-int iswlower_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-int iswprint_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-int iswpunct_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-int iswspace_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-int iswupper_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-int iswxdigit_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
+int iswalnum_l(wint_t __wc, locale_t _Nonnull __l);
+int iswalpha_l(wint_t __wc, locale_t _Nonnull __l);
+int iswblank_l(wint_t __wc, locale_t _Nonnull __l);
+int iswcntrl_l(wint_t __wc, locale_t _Nonnull __l);
+int iswdigit_l(wint_t __wc, locale_t _Nonnull __l);
+int iswgraph_l(wint_t __wc, locale_t _Nonnull __l);
+int iswlower_l(wint_t __wc, locale_t _Nonnull __l);
+int iswprint_l(wint_t __wc, locale_t _Nonnull __l);
+int iswpunct_l(wint_t __wc, locale_t _Nonnull __l);
+int iswspace_l(wint_t __wc, locale_t _Nonnull __l);
+int iswupper_l(wint_t __wc, locale_t _Nonnull __l);
+int iswxdigit_l(wint_t __wc, locale_t _Nonnull __l);
 
-wint_t towlower_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-wint_t towupper_l(wint_t __wc, locale_t _Nonnull __l) __INTRODUCED_IN(21);
+wint_t towlower_l(wint_t __wc, locale_t _Nonnull __l);
+wint_t towupper_l(wint_t __wc, locale_t _Nonnull __l);
 
 wint_t towctrans_l(wint_t __wc, wctrans_t _Nonnull __transform, locale_t _Nonnull __l) __INTRODUCED_IN(26);
 wctrans_t _Nonnull wctrans_l(const char* _Nonnull __name, locale_t _Nonnull __l) __INTRODUCED_IN(26);
 
-wctype_t wctype_l(const char* _Nonnull __name, locale_t _Nonnull __l) __INTRODUCED_IN(21);
-int iswctype_l(wint_t __wc, wctype_t __transform, locale_t _Nonnull __l) __INTRODUCED_IN(21);
+wctype_t wctype_l(const char* _Nonnull __name, locale_t _Nonnull __l);
+int iswctype_l(wint_t __wc, wctype_t __transform, locale_t _Nonnull __l);
 
 __END_DECLS