Windows Phone 8 support to end in July 2014 but users will be able to upgrade

Microsoft has announced the support dates for its mobile operating systems, Windows Phone 8 and Windows Phone 7.8, on its Support pages. The listing, which was first spotted by Italian website, Plaffo, reveals that Microsoft will support Windows Phone 7.8 till September 2014, and Windows Phone 8 till July 2014.
 
This implies that Microsoft will make updates available for the Operating System on the user's phone, including security updates, for a period of 18 months from the lifecycle start date. However, Microsoft clearly mentions that distribution of the updates could be controlled by the mobile operator or the phone manufacturer and that update availability will also vary by country, region, and hardware capabilities.
 
Microsoft has also issued a statement, which was published by The Seattle Times blog, clarifying that Windows Phone 8 users will be able to upgrade to the next version of Windows Phone when it comes out. The company said:
 
"As we've said, one benefit of moving to the Windows core is that Windows Phone 8 is upgradeable. This means that even beyond the updates we're committing to distribute for 18 months, Windows Phone 8 devices will be able to upgrade to the next version of Windows Phone when it is launched."
 
The WindowsPhone twitter handle also tweeted that Windows Phone 8 was upgradeable due to its Windows core.

This means that Windows Phone 8 devices would be able to upgrade to the next version of the operating system. But as with other updates, the upgrade would also depend on the phone manufacturer and carrier.
 
Microsoft is said to be working on Windows Phone Blue, the successor to Windows Phone 8. It had earlier rolled out the Portico update to Windows Phone 8 devices.
 
As an aside, it's interesting to note that Windows 8 will be supported till September 2018.