Exchange Online dropping support for Office 2007 from Oct 31 2017

RPC over HTTP, also known as Outlook Anywhere, will no longer be a supported protocol for accessing mail data from Exchange Online as of Oct 31, 2017. Microsoft will no longer provide support or updates for Outlook clients that connect through RPC over HTTP, and the quality of the mail experience will decrease over time.

This is being replaced by MAPI over HTTP, a modern protocol that was launched in May 2014. This change affects you if you're running Outlook 2007 because Outlook 2007 won't work with MAPI over HTTP. To avoid being in an unsupported state, Outlook 2007 customers need to update to a newer version of Outlook or use Outlook on the web.

This change may also affect you if you're running Outlook 2016, Outlook 2013, or Outlook 2010 because you must regularly check that the latest cumulative update for the version of Office that you have is installed.

What is RPC over HTTP? What happens on October 31, 2017?

RPC over HTTP, also known as Outlook Anywhere, is a legacy method of connectivity and transport between Outlook for Windows and Exchange. In May 2014, Microsoft introduced MAPI over HTTP as a replacement for RPC over HTTP.

Starting on October 31, 2017, RPC over HTTP will no longer be a supported protocol for accessing mail data from Exchange Online. Starting on this date, the following conditions will apply:
1. Microsoft will not provide support for RPC over HTTP issues (regular or custom).
2. No code fixes or updates to resolve problems that are unrelated to security will be released.

Additionally, for Office versions that support MAPI over HTTP, Microsoft may elect to override existing registry keys that customers are using in order to force RPC over HTTP use.

Why is RPC over HTTP being replaced by MAPI over HTTP?

MAPI over HTTP offers the following benefits:
• Improves the connection resiliency when the network drops packets in transit.
• Enables more secure sign-in scenarios, such as multi-factor authentication for Office 365.
• Provides the extensibility foundation for third-party identity providers.
• Removes the complexity of RPC over HTTP dependency on legacy RPC technology.