Yes, there is a chance - in fact, Microsoft mentioned that all Windows Phones running 8.1 should be capable of being upgraded to Windows 10 - but the question is when it will be released. As of now, there seems to be no specific date for the release of Windows 10 for phones, but what has been mentioned by Microsoft is that it will be released towards the end of the year (2015). That may or may not mean that the update will be available before 2016, since there's a chance that the update will be spread out across several months to cover all devices in all regions of the world.