Will my rules/best practices stop working when we migrate to a new version of ODI?

No. The rules/best practices are version independent. However, we provide communication to all our clients on any possible hurdles well in advance and provide road-map to migration/upgrade. Our key objective is to develop and test the best practices(new and old) as soon as Oracle announces new release. In a highly unlikely scenario where our customers require migrating ahead of our having certified the rules against the new release of Oracle Data Integrator (ODI), we will discuss this with the customer to provide them a least disruptive course of action.