The stage that follows test release is the production release. When all User Stories are completed and everything is tested, the client has the final say on whether there is a Minimum Viable Product (MVP).
An MVP is a product that has just enough features to satisfy early customers. It is a great way to get feedback that can be used for future development since it targets building products that customers want and need.
The product release stage is where the life of a product starts on the market.
The final stage of the Product Development Lifecycle is the Maintenance.