Chapter 12. Upgrade

Chapter 11 covered installation; this chapter focuses on upgrades. Upgrades are often more problematic than installations because they can cause customers substantially more pain: Data can be lost, stable integrations with other systems can break, and old features may work differently (or even not at all). Handling upgrades well is key not just to creating winning solutions but to sustaining them through multiple releases. Given that more money is made on upgrades than on initial sales, and that one of the primary functions of marketing is finding and keeping customers, it is surprising that upgrades receive so little attention from marketects and tarchitects.