Sencha released Ext JS 5 on June 2014. Ext JS 5 includes many new features along with support for MVVM (Model-View-ViewModel) architecture. It is truly a multi-device JavaScript framework that supports tablets and touch screen desktops.
These tutorials will teach you some of the new features of Ext JS 5 such as ViewModel, ViewController, Session, Chained Store etc.
Basic knowledge of Ext JS 4.x and JavaScript is required.