If you decide to store requirements links in an external file, keep the following guidelines in mind:
When sharing models, use the default name and location.
By default, external requirements are stored in a file named model_name.req in the same folder as the model. If you give your model to others to review the requirements traceability, give the reviewer both the model and .req files. That way, when you load the model, the RMI automatically loads the links file.
Do not rename the model outside of Simulink®.
If you need to resave the model with a new name or in a different location, in the model window, use File > Save As. Selecting this option causes the RMI to resave the corresponding .req file using the model name and in the same location as the model.
Be aware of unsaved requirements changes.
When you change a Simulink model, an asterisk appears next to the model name in the title bar, indicating that the model has unsaved changes. If you are creating new requirements links and storing them externally, this asterisk does not appear because the model file itself has not changed. You can explicitly save the links, or, when you close the model, the RMI prompts you to save the requirements links. When you save the model, the RMI saves the links in the external file.