We're made the transition from A news to B news, following our upstream feed, Utzoo. The switch began on May 8th 1982. There were a few duplicate articles received on both A and B news. At this point, all new articles are from B news; the switch is complete.
At this historical remove, there's not a lot of visible difference between the A news and B news articles you will see in your news reader. One nice thing is that there are a pair of headers that show how long it took a message to propigate to Utzoo:
Posted: Mon May 10 13:25:04 1982 Received: Tue May 11 03:32:32 1982
In all, 11 thousand A news articles have reached olduse.net. There will be a lot more B news articles!
Update: Turns out that modern newsreaders don't do a good job of displaying From headers that contain only a UUCP bang path. Who knew? Rather than fixing all the news readers, I'm putting in a hack to the From headers of articles posted after this point.