As other companies offered comfort and styling advantages at competitive prices, the Model T lost market share and became barely profitable. Design changes were not as few as the public perceived, but the idea of an unchanging model was kept intact. Eventually, on May 26, 1927, Ford Motor Company ceased US production and began the changeovers required to produce the Model A. Some of the other Model T factories in the world continued for a short while, with the final Model T produced at the Cork, Ireland plant in December 1928.

Source: Wikipedia