Hello All,

I am planning to build an Outlook app and/or add-in, and am debating the merits of developing for Exchange 2010 or 2013 initially. Given the new app support for 2013, it seems like that would be the easiest from a development standpoint. However, most of the enterprise market is probably still running 2010. Does anyone know the market breakdown is for enterprise usage between versions 2007/10/13? If nobody is running 2013 yet, we don't want to waste our efforts. Knowing those rough statistics would be a huge help.

Thank you to anyone who can shed some light on this!

I would suggest you read http://windowsitpro.com/blog/comparing-office-365-numbers-total-exchange-installed-base

Cheers
Glen