The latest issue over Overland Journal, the quarterly of the Oregon-California Trails Association (OCTA), is full of Donner Party material, including some new primary documents.
First are three letters by rescuer Selim E. Woodworth. Two were written while he was on the trail to Oregon in 1846, the third on February 6, 1847, the eve of his departure to the mountains to rescue a party of "unfortunate emigrants" starving in the mountains.
Then there's my article about survivor Sarah Graves Fosdick and the Graves family, followed by another "new" (i.e., previously unknown) letter that Sarah wrote to relatives in Indiana to inform them of the disaster. Sarah wrote on May 23, 1847, a day after her sister Mary wrote to Sarah's father-in-law back in Illinois, and the two letters are very similar (Mary's letter is in Unfortunate Emigrants, p. 129-131).
These new primary documents are pretty minor and certainly don't revolutionize our knowledge of the Donner Party, but they're still very interesting. Woodworth's trail letters help fill a gap in our knowledge of the emigration of 1846; Sarah's is a real gem not so much because of its content but because of the personal angle -- it's her only account of the Donner Party, written soon after the tragedy, and one of the very few documents by her known to exist.
In addition to these articles, this issue of OJ also has a piece by Rush Spedden, "The Donner Trail Across the Salt Lake Valley." In this detailed inquiry, Rush argues that the Donners crossed the Jordan River at 3300 South, over half a mile from the location (2700 South) posited by Dale Morgan and Roderick Korns in West from Fort Bridger. Rush make a pretty good case and it'll be interesting to see how the experts respond.