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Changes in the Best body format POP3 and IMAP4 retrieval option in Exchange 2007 SP3 Update Rollup 1

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Microsoft Exchange Server 2007 will reach end of support on April 11, 2017. To stay supported, you will need to upgrade. For more information, see Resources to help you upgrade your Office 2007 servers and clients.

 

This topic describes a content retrieval change that was introduced in Microsoft Exchange Server 2007 Service Pack 3 (SP3) Update Rollup 1. This change affects how POP3 and IMAP4 clients retrieve MIME messages from Exchange 2007 Mailbox servers.

Overview

Exchange 2007 includes the following MIME message retrieval options for POP3 and IMAP4 clients:

  • Text

  • HTML

  • HTML and alternative text

  • Enriched text

  • Enriched text and alternative text

  • Best body format

By default, Exchange 2007 uses the Best body format option for POP3 and IMAP4 message retrieval.

The Best body format retrieval option represents the native content of a message that is stored on a server that is running Microsoft Exchange. This format retrieval option is used to reduce the likelihood of unnecessary content conversion operations on the server. Because POP3 and IMAP4 client protocols do not let clients specify Exchange content retrieval options when they retrieve messages from Exchange, the message retrieval options must be configured on the server that is running the Exchange Client Access server role. These settings control how the content is requested from the Exchange Mailbox server and how the content is sent to the POP3 or IMAP4 clients.

You can use the Exchange Management Shell or the Exchange Management Console to manage the message retrieval options for POP3 or IMAP4 users. For more information, see How to Manage POP3 and IMAP4 Message Retrieval Format Options.

Change in the "Best body format" retrieval behavior in Exchange 2007 SP3 Update Rollup 1

Exchange 2007 SP3 Update Rollup 1 introduces a change in the behavior of the Best body format retrieval option. In some situations after you apply Exchange 2007 SP3 Update Rollup 1, legacy POP3 or IMAP4 clients may be unable to render content that is retrieved from an Exchange 2007 Client Access Server (CAS).

In versions of Exchange 2007 that are earlier than Exchange 2007 SP3 Update Rollup 1, the Best body format option is functionally equivalent to the HTML and alternative text retrieval option. In this scenario, POP3 or IMAP4 clients that use the Best body format or HTML and alternative text retrieval option receive an HTML message together with a text-only copy of the message. This lets clients that cannot render the HTML message format view the text copy of the message.

When you apply Exchange 2007 SP3 Update Rollup 1, the behavior of the Best body format option changes. In this scenario, POP3 or IMAP4 clients that use the Best body format option only retrieve the native content that is stored on the Exchange Mailbox server. The POP3 or IMAP4 clients no longer receive an additional text-only copy of the message. If a POP3 or IMAP4 client cannot render the HTML message content, the client may be unable to view the retrieved message content.

If you require the earlier behavior of the Best body format option in an organization, modify the POP3 or IMAP4 retrieval settings to use the HTML and alternative text retrieval option. You must configure these settings on every Exchange 2007 Client Access server that provides services to POP3 or IMAP4 clients. After you modify these settings, you must restart the following services, as appropriate:

  • Microsoft Exchange POP3

  • Microsoft Exchange IMAP4

For more information about how to modify POP3 and IMAP4 message retrieval options, see How to Manage POP3 and IMAP4 Message Retrieval Format Options.

More Information

For more information about how to manage POP3 or IMAP4 retrieval options in Exchange 2007, see Managing POP3 and IMAP4.

For more information about how to obtain Exchange 2007 SP3 Update Rollup 1, see How to Obtain the Latest Service Pack or Update Rollup for Exchange 2007.