I think "Vecna" came out three months ago. You must run a fast-paced game.
I'm glad your group had a good session.
Our sessions are played online on Roll20 and theoretically run for 3 hours, but it's more like 2.5 hours after time spent catching up.
The full breakdown of how it went:
Session 1: May 13 (Chapter 1)
Session 2: May 20 (Chapter 1)
Session 3: May 27 (Chapter 2)
Session 4: June 3 (Spelljammer)
Session 5: June 10 (Spelljammer)
Session 6: June 17 (Eberron)
Session 7: June 24 (Ravenloft)
Session 8: July 01 (Ravenloft)
Session 9: July 08 (Ravenloft)
Session 10: July 15 (Dragonlance)
Session 11: July 22 (Dragonlance)
Session 12: July 29 (Greyhawk)
Session 13: August 05 (Greyhawk/Planescape)
Session 14: August 12 (Planescape + Chapter 9)
Session 15: August 19 (Chapter 10)
Session 16: August 26 (Chapter 10 + Chapter 11)
Session 17: September 2 (Chapter 11, finis)
** still to come as I write this
There's a little more overlap, but that's the bulk of how it played. Most DMs will flesh out sections a LOT more than I do, but a large part of how I run stuff is to concentrate on major story beats. I also run combat fast, so that moves things along.
That said, some of the chapters are very slight in material. Chapter 9 especially. I can see how some roleplaying orientated groups can expand that significantly, but I tend not to expand roleplaying unless it's actually provides interesting choices or I really vibe with the characters. The Wizards Three... don't come off well in this adventure, despite my personal love of playing Mordenkainen.
Cheers,
Merric