NNTP question about getting new headers

[nm_114]

I hope this is the right forum... I'm confused about how you get new headers from a newsserver. I guess when you first suscribe to a group you get what is already on the server by sending a GROUP command to get the the low and high article numbers and send an XOVER command with these two values. But to get new headers later, do you add 1 to that high article number and send the GROUP command again to get the new high article number and then send the XOVER command with these two values? If this is the case, what happens when the high article number is greater than the maximum int value? Does it wrap around from 0, which would make the high article number lower than the low article number? - thanks