In my experience, Supplier notification for custom components is extremely important for companies that outsource some of their components. At my company, it is required to send the supplier a notification of the updated specifications and they must sign to accept the changes. I think this contributes to the working relationship with suppliers and helps identify any parameter changes that the supplier cannot support. Additionally, if suppliers are not fully aware of the changes to the components, they can fail to implement the intended changes and ultimately lead to part rejection or the device being made not to specification.