The blue "Build Code" button in Simulink only appears if you have Simulink Coder and/or Embedded Coder installed. It seems like the upgrade did not install these products on your machine.
To solve the issue, on the MATLAB Home tab:
1. Navigate to Environment -> Add Ons
2. Search for MATLAB Coder (prerequisite).
3. Click Install and follow the instructions.
4. Go back to Add Ons.
5. Search for Simulink Coder or Embedded Coder (or both, depending on your use case).
6. Click Install and follow the instructions.
7. Open your Simulink model and the button should now appear.
If the button is still missing, please contact MathWorks Technical Support for additional help:
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