The lifecycle information about the two mobile operating systems came to light after Plaffo.com spotted the information on Microsoft Product Lifecycle Search page. The exact dates as noted by Microsoft are September 9, 2014 for Windows Phone 7.8 and July 8, 2014 for Windows Phone 8. This means that both the operating systems are going to receive updates for duration of 18 months.
Windows Phone 8 is the latest version of OS from Microsoft which introduced some new features like Live Tiles and new lock screens. Nokia Lumia 920 Windows Phone 8X from HTC were the first phones to get the taste of this new OS. Microsoft also released Windows Phone 7.8 for old smartphones which were not eligible for the new update.
Microsoft has always been very transparent about its plans for supporting the older platforms. Last November Microsoft revealed that it will stop supporting Surface RT tablet running Windows RT in April 11, 2017. Usually Microsoft supports its software products for 10 years but considering the emerging smartphone and tablet market, Microsoft have to take these steps. Today many leading smartphone and tablet manufacturers update their flagship device every year but they do continue to support previous devices for few months or years.