The Obsolescence state means that the product is terminated. It cannot be bought, and will not be supported by us, but third-party support may be available. All product revenue has been captured, although expenses still may occur (depending on the terms and conditions of past sales). Concerns include:
In our model, there is a 0.2 probability each quarter that a project will move from the Obsolescence state to the Maintenance state. There is a 0.8 probability that the project will remain in the Obsolescence state. This indicates that we have no strong need to disassociate ourselves from previous products. If a customer can afford for us to restart Maintenance, we are happy to do so. Our model does not reflect a possibility that a project may be permanently abandoned in the Obsolescence stage. There is always a price at which it makes sense to go back to Maintenance, even for only one key customer.
If the Coupling From The Past algorithm results in the Obsolescence state, this means that the Obsolescence state always occurred at time t=0, regardless of what states occurred at any time in the past.