When faced with a significant change that impacts the project scope or environment, such as the termination of operating systems, the first action should be to engage with stakeholders to assess the impact. This is in line with the agile principle of collaboration and early stakeholder engagement. By scheduling a session with stakeholders, the project manager can gather insights on the implications of the change, which is essential for informed decision-making and planning. This approach is supported by the PMBOK Guide, which emphasizes the importance of stakeholder engagement and communication when dealing with project changes. Additionally, the Professional in Business Analysis (PBA) materials highlight the need for business analysis to understand the requirements and constraints of the stakeholders, which is critical in this scenario to determine the next steps for the project.
: PMBOK Guide and Professional in Business Analysis (PBA) Reference Materials.

When a product owner requests the addition of a new mandatory feature during a sprint, it can disrupt the planned work and cause frustration within the team. The best course of action is to engage the product owner in prioritizing the product backlog with the project team. This collaborative approach ensures that the team understands the value and urgency of the new feature, aligns on the priorities, and adjusts their work plan accordingly. It also helps in managing the team's workload and expectations, preventing overcommitment and potential burnout. By prioritizing the backlog together, the team can make informed decisions about what work to focus on during the sprint, ensuring that the most critical features are delivered first.
Professional in Business Analysis Reference Materials source and documents.

The first action in resolving this type of conflict is to engage in direct communication with the contract department. This approach aligns with conflict resolution techniques recommended for business analysts, which emphasize discussion and negotiation to reach an agreeable solution2. By arranging a meeting, the project manager can foster a collaborative environment, acknowledge the contract department's importance to the project, and work towards a mutual understanding and commitment. References: = Exam PMP topic 1 question 204 discussion - ExamTopics, Conflict Resolution Techniques for Business Analysts - Adaptive US.

One of the core values of agile is to deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale1. This means that the project manager should seek ways to show the customer the value of the software as early and often as possible, rather than waiting for the final deliverables or a major milestone. By evaluating various delivery options, such as demos, prototypes, beta versions, or minimum viable products (MVPs), the project manager can get feedback from the customer and validate their needs and expectations. This will also help the project manager to prioritize the features that deliver the most value to the customer and align the team's efforts accordingly. The other options are not as effective as evaluating various delivery options. Asking the internal sales team to keep the customer informed of the delivered value may not be sufficient, as the customer may not be able to see or experience the software for themselves. Informing the customer about the progress and updating them on the final deliverables may not be enough, as the customer may not be satisfied with the outcome or may have changed their requirements. Waiting for an important milestone to complete and then informing the customer of the progress may be too late, as the customer may have missed the opportunity to provide feedback or suggest changes. References:
* The 12 Agile Project Management Principles: Key Pillars of Agile
* Focusing on Customer Value with Agile Program Management
* What is Value-Driven Delivery in the agile world? - Whizlabs