So, I didn't see anything on this with a brief search, but two things I've noticed in playing 40.03 that I wanted to share.
First, orphans can survive from baby to childhood now (I can see the look of horror on some your faces already)! I had a baby that arrived in her mother's arms as a migrant. Said mother promptly climbed a tree, fell out of that tree, and ended up in a pond, where she drowned. Somehow the baby managed to survive this (I wasn't paying close attention at the time, I arrived on the scene after she drowned and the baby was crawling around outside). This baby, Etur by name, had a father who arrived too, but let's face it; mother dwarves do all the work, and fathers none.
The baby crawled eventually into the fortress and there wandered its halls for about a year. During that time, food and water was brought to Etur regularly by, mostly, my Chief Medical dwarf (so chosen for his compassion and desire to help others). Eventually, little Etur grew to a child, and is now capable of feeding and drinking on her own. Good to see the various game mechanics involved in that scenario appear to be working well!
Second, after about two years in, my fort started to see some real FPS drops. Like, 12 and 13 FPS moments. Primarily this is because I genned it on a max size world that was 150 years old. No biggy, Toady has mentioned he has calendar optimizations to do. But, as an experiment, I retired the fort, then reclaimed it. Once reclaimed, I noticed a definite average improvement in my FPS; back to a 60 and 70 FPS average in the roughly one week of game time that I played it after reclaiming. Definitely something to keep in mind.
However, as a side note, I don't recommend doing the retire/unretire when there are merchants on your map. All the merchants and their livestock were friendly upon reclaim, but four caravan guards remained as well when I reclaimed, and all four of them were marked as hostile in the unit screen.
So, there you have it. A couple more tidbits of info about the new version.