diff --git a/libc/include/signal.h b/libc/include/signal.h
index d9f43de..3905d86 100644
--- a/libc/include/signal.h
+++ b/libc/include/signal.h
@@ -144,8 +144,8 @@
 
 extern int sigaltstack(const stack_t*, stack_t*);
 
-extern void psiginfo(const siginfo_t*, const char*) __INTRODUCED_IN(21);
-extern void psignal(int, const char*) __INTRODUCED_IN(21);
+extern void psiginfo(const siginfo_t*, const char*) __INTRODUCED_IN(17);
+extern void psignal(int, const char*) __INTRODUCED_IN(17);
 
 extern int pthread_kill(pthread_t, int);
 extern int pthread_sigmask(int, const sigset_t*, sigset_t*);