---
title: Message Header Elements (S.205)
slug: eprescribing/guide/message-header-elements-s205
docTags: 
createdAt: 2026-07-09T20:40:17.586Z
---

# Overview

This section holds the application certification requirements located in the [Message Header Elements](docId\:czdkqc3-XhKcw1B-EjDDX) section in the guide.

## S.205

**S.205:** The sender shall ensure the combination of the From and MessageID elements, for all messages including Error, is unique for at least 18 months. Surescripts recommends an unformatted Globally Unique Identifier (GUID).