It's my question. Currently our customer satisfied with our product, what is needed to change the quality of product or same?

In keeping your old clients or in getting new prospects, even if you're changing to a new product line or even promoting a new one, just make sure to retain the same quality or even making it higher.

ways to improve quality

Make a commitment.    

 Track mistakes.

 Invest in training.

Organize quality circles.

Have the right attitude.

If you will change the quality that means different price , So will your current customer accept that? . You should consider that first

twice to make customer more loyalty 

I apologize for the answer I leave the answer to the specialists experts in this the field that's not my area.