It's a fact – Exchange 5.5 and Exchange 2003 still have the majority share of Exchange deployments around the world. However, with Exchange 2010 hot on the heels of Exchange 2007 there's a dilemma now about upgrading.
I know I need to move from Exchange 5.5/2003, but do I upgrade to 2007 which is understood, tried and tested now, or jump to Exchange 2010?
Early adoption of Exchange 2007 was difficult; firstly it required the move to a 64-bit platform, remember - in 2007 you still had to make the purchasing choice and pay a premium for 64-bit hardware. Also, Exchange 2007 saw a technological shift from Exchange 2003 with a different storage model, new clustering and availability technologies, and new roles with CAS/HT etc. Organisations need time to understand this – there are technical skills to develop, architectures and roadmaps to develop, and projects and budgets to fit in with. This caused slow adoption of Exchange 2007 by the mainstream corporate market. You can see this from the big Exchange marketing push that Microsoft made in the summer of 2008 – the pace of adoption for Exchange 2007 was below expectations.
While 5.5 and 2003 may have their limitations, they are trusted and reliable email platforms which organisations depend upon. But, here's a new problem... mainstream support of Exchange 2003 has now come to an end. What's the difference between Mainstream Support and Extended Support? When a product moves into Extended Support, Microsoft will provide for Paid Support and Security updates only. You do NOT get Non-security hotfix support, no-charge incident support, warranty claims, or support for any design changes and feature requests. Beyond this you have access to online self-help support only, i.e. the Microsoft Knowledge Base, or you have to pay for support. (~£140/hour, help yourself - http://support.microsoft.com/gp/lifepolicy) or you can buy Custom Support from Microsoft if you have a dependency on Exchange server.
OK, so that's not the end of the world, in fact it went into Extended Support in April 2009 and you didn't even notice! If you don't mess with it, an Exchange server will keep running 24/7 and will continue to provide enterprise email and services to you users for many months or years to come. However, you will need to move sometime – after don't get caught out on an unsupported and ineffective platform. Overtime, the upgrade options available to you become harder to swallow – moving from Exchange 5.5 to Exchange 2007 isn't so simple.
As ever, there are many options available if you're at this crossroads. One to consider – go hosted by moving your Business Email to a provider of Hosted Exchange. You can even make considerable savings on your Microsoft licensing agreements too!