This is a bad news for all WhatsApp users that still working on the old operating systems.
Older operating systems on Apple and Android devices will no longer be supported by the App.IPhone users running on iOS 8 or earlier and Android customers with versions 2.3.7 and older will be locked out next month.
So before its too late and to avoid losing your chat,you must save their data before they are locked out of the app, by going to Group Info and Export Chat.
To mention that WhatsApp is most populous instant messaging App founded in 2009 by two former Yahoo employees, Brian Acton and Jan Koum. With more than 1.5 billion users in 180 countries . In February 2014 Facebook inc has acquired WhatsApp for US $19 billion, considered as the largest acquisition to date.