Dedicated Server: versions

[Fr0stbyte124]

When I try to join some dedicated server games, the game tells me my client is an earlier version than the server. However, I have Halo v. 1.04, for both the game and the server, and I can play games on the main list just fine.

Looking into it further, I see that there are two different builds of v. 1.04:
01.00.04.0607 and 01.00.04.0609.

But clearly there is only one update patch available, so where are these 01.00.04.0609 servers comming from?