People often seem to get tripped up by this, so document more clearly

data/example.conf

@@ -1068,6 +1068,8 @@ mail
 	/*
 	 * This is the encryption type used by the databases. This must be set correctly or
 	 * your passwords will not work. Valid options are: md5, oldmd5, sha1, and plain.
+	 * You must also be sure to load the correct encryption module below in the Encryption
+	 * Modules section so that your passwords work.
 	 */
 	#hash = "md5"
 }
@@ -1229,8 +1231,9 @@ module
  * encrypted by this module. Old passwords stored in another encryption method are
  * automatically re-encrypted by the primary encryption module on next identify.
  *
- * NOTE: enc_old is Anope's previous (broken) MD5 implementation, if your databases
- * were made using that module, continue to use it and do not use enc_md5.
+ * NOTE: enc_old is Anope's previous (broken) MD5 implementation which is present in
+ * versions prior to Anope 1.7.17. If your databases were made using that module,
+ * use this and not enc_md5.
  *
  * NOTE: enc_sha1 relies on how the OS stores 2+ byte data internally, and is
  * potentially broken when moving between 2 different OSes, such as moving from