Igor Minar from the Angular Team at Google made this announcement at NG-BE 2016 conference in Belgium. Minar also revealed Google plans for releasing a major Angular version every six months.
Google released Angular 2.3 earlier this month. The update brought Angular Language Service designed to integrate with IDEs for completion and error checking with Angular Templates.
Just few weeks before the latest release, Google brought Angular 2.2 in November. With this rate of new releases, it is quite confusing for users to keep track of the numbers.
Having said that, it is indeed evidently confirmed that Google’s plan for Angular is aggressive. You can expect eight beta releases of Angular 4 before the final release in March. Also, Angular 5 is scheduled to be available by October 2017.