WhatsApp Messenger is Cross platform apps messaging service.
Maybe yes,maybe no.
WhatsApp will discontinue support for some older operating systems in the late 2016's. Including BlackBerry OS and Nokia
Quoted from Venture Beat, the popular Facebook's messaging service that stop support for all Blacberry OS including BlackBerry 10,Nokia S40 and Nokia Symbian S60. In addition, the old Android OS 2.1, 2.2 and Windows Phone 7.1.
WhatsApp argues they will only focus on the operating system that is used by many people.
"When starting WhatsApp in 2009, the use of mobile devices is very different from now. App Store is still a few months old. Approximately 70% smartpone sold at that time operating system BlackBerry or Nokia," wrote WhatsApp.
"The operating system offered by Google, Apple and Microsoft covers less than 25% (now 99.5%) of all mobile devices sold at that time. As we look to the future to 7 years, we intend to focus our efforts on mobile platforms used the majority of people, "said WhatsApp.
WhatsApp also suggested that users move from a platform that is not supported. This is to make sure they still get the latest updates feature