If you are a Windows Insider and already have preview 10536 running on your phone, you are stuck. That is to say, your phone will not get any further Insider updates. For some reason, Microsoft has decided that you have to downgrade back to Windows Phone 8.1 first and then get back in the Insider programme in order to be able to get subsequent updates like build 10549 and above.
Will you be downgrading to enjoy further updates?
