diff --git a/library/md.c b/library/md.c
index 381ffc4..1d6191f 100644
--- a/library/md.c
+++ b/library/md.c
@@ -54,6 +54,9 @@
     volatile unsigned char *p = v; while( n-- ) *p++ = 0;
 }
 
+/*
+ * Reminder: update profiles in x509_crt.c when adding a new hash!
+ */
 static const int supported_digests[] = {
 
 #if defined(MBEDTLS_SHA512_C)