## 5 Findings  
Based on the interviews conducted with the four companies of different sizes, the initial model has been evaluated and improved. The findings of the evaluated initial model in Figure 1 are summarized below. The initial model provides an overview of primary, secondary, and next lifecycles, which can be used for the long-term planning of product lifecycle management, including considering several **new and emerging existential design aspects**. The additional key findings, part of the initial model, are highlighted below:  
* There may be a need for **iterations between the requirements and design, development, and test phases** to sort out the requirements and make design aspects, such as design-for-X, translated into actual and testable requirements. Otherwise, there is a risk that many design aspects are not formally tested or properly documented as (detailed) requirements:  
Figure 1: Initial model concerning extending product lifecycles to achieve long and extendable lifecycles in the light of new and emerging existential design aspects. Digital/connected products should be designed to be updatable and upgradable regarding software and partly hardware in combination, preferably using advanced cybersecure fleet management functionality. Concerning non-connected or regular products, these may need a lot of similar functionality but may require manual measures to update, upgrade, maintain, check wear and tear, as well as monitor the need for maintenance, etc. These properties are needed to maintain an adequate cybersecurity level throughout the products' lifecycles and to comply with, for instance, the EU's new and emerging legal and regulatory requirements. Other regions in the world will likely pose similar, or in the worst case quite different, legal and regulatory requirements; therefore, if one is a global provider of products, a lot of surveying is necessary. Connected or not, at the end of the primary lifecycle or any of the following ones, erasing and wiping of data, information, IPR, software, etc., should be made to not provide any IPR to competitors or clues to hackers (enabling attacks toward the environment where the product was installed). * **Availability of key raw materials, components, external software, etc., used needs to be ensured**. This will likely result in significant changes in the structure of value chains/networks to avoid the same problems as experienced during the recent COVID-19 pandemic with political decisions, Suez and Panama Canal problems, as well as war and terrorist activities, such as in Ukraine and the Red Sea, which had a grave impact on supply and availability. Further, the new and emerging existential design aspects may also impact the availability of software and hardware at least until providers have adapted or new ones need to be sourced. Thus, the expected availability should be investigated if not already made, and actions should be taken to minimize risks related to the availability of raw materials, components, and external software. * **The selection of a business model is key for long and extendable product lifecycles**. Business models enabling the provider to retain the ownership, such as **subscriptions, leasing, product-service systems, or functions**, provide the possibility for better control and management of the product and possibilities to efficiently maintain, service, and support the product in operations until the very end of the last lifecycle. To summarize the findings, design methods, development processes/models, or lifecycle models, etc., used to manage a product's lifecycle and, in particular, the interaction between the requirements and design, development, and test phases may need to be adjusted, and iterations should be added in between to be able to capture all necessary and existential design aspects so that these are formally included into the design, functional, and test specifications. Otherwise, there will be no traceability, and compliance requirements may be hard to verify in practice.