Complex sentence: The first phone based on the platform is the Nokia Asha 501, and were followed by the Asha 500, Asha 502 Dual SIM, and Asha 503, all announced at Nokia World in October 2013.
Split into simpler sentences: The first phone based on the platform is Nokia Asha 501. Successor models Asha 500, Asha 502 Dual SIM, and Asha 503 were all announced at Nokia World in October 2013.