How do to best handle changes to messaging based on evolution of product features?

Customer Centricity is Key

The best way to handle products that are ever changing is to build a solution centric narrative. 

If you build your narrative around solutions or customer-centric needs, then this shouldn’t change with a few feature add-ons. Customer needs tend to change less often than product features. Think of features as pillars or building blocks to support your narrative. A strong, well researched and tested narrative will not collapse if you need to replace one feature with a newer one.

A good way to think of your narrative is to imagine a house. The foundation of your house is the platform or product. On top of the foundation there are pillars that will hold the infrastructure together, these are your product features, not visible externally but very important to hold your story together. The roof that sits on top of those pillars can be considered your solutions, meaning, and the benefits that your features will add. All of these elements (foundation, pillars and roof) are normally built by engineers.

Your job as a product marketer is to design the house, plan how all the elements will connect in harmony and how the house will be perceived by the external audience. The Product Marketer is the architect of the house. And a good architect will design a house in such a way that if one pillar falls or needs to be replaced, the house will still maintain its function and design. If you architect your narrative with your audience in mind (instead of the product), adding a new feature should enhance it; not change it.