[Sengrik Sangma]

I am running build 1439 but I am not sure whether it is the latest build or not. When I check for update it shows that the device is up to date.

[shmsnh]

Are you asking about the Release Preview ring? That ring is on 14393.594, I believe.

[Sengrik Sangma]

thank you for replying. I am actually asking about the Fast Ring.

[demon09]

14986 is the latest on fast ring as of today. There's a sub-forum here for Insider builds and info too, if you're interested in reading about the builds and issues Windows 10 Insider Preview - Windows Central Forums

[Doug Noyce]

As of Jan 9, 2017, Windows Insiders on the Fast Ring have received Update 15002 for auto-update.