Answer:
Improvements or revisions of existing products
Explanation:
The creation of new series or models of a product might see companies go all out to make wholesale changes which will be like a complete overhaul of the precious or current model or companies may opt for a mild changes in the existing product such as allowing for more variant, upscaling on the current model which will be termed as a sort of upgrade or improvement on the existing product. Based on the changes reported about the upcoming BMW 3 series, we can see from the changes made that there are no design or whole sale changes in the series, just an improvement in functionalities and more variant option of the existing model.