Glen Drover has posted the following message in the forum section:

"As I write this letter to you, Dave (Mustaine) is recording some of the vocals for the new album and he is sounding great! We are all having a great time here finishing up the tracks for this album here in California and the weather is awesome! As for myself, I have done a few solo pieces, which I am very happy with. Lots of crazy solos on this album people!"

Source Megadeth