Implementation of many new features without complicating the site itself. Examples of completed tasks: adding a new tab "Cross currency rates". Where one currency against another is calculated. Rates are drawn from an internal system that is updated automatically every day. Also, the task of creating a mortgage calculator was completed, which from the order form pulls in the entered data and calculates the loan amount, and the corresponding balance for each of the months of crediting.
Specific discussion, and the most detailed acquaintance with the banking system of data transmission, and then agreeing with the client of the planned work.
Due to the detailed analysis and full agreement from the customer, we were able to complete the task without having to suspend the site.