I tried following the above instructions on how to upgrade to 15.1, and I cannot successfully upgrade even if my life depeneded on it. Either my Nvidia drivers get replaced with another set of drivers which leave me at a black screen, or I encounter some of a kernel panic immediately after the boot menu, which then causes my system to reboot after fifteen seconds. Unfortunately I'm stuck at 15.0 for the next few days, but I think that I need to start thinking about doing a complete reinstall using the ISO for 15.1, or I may have simply retreat from FreeBSD for a while. I guess I had better sleep on it before I make any decisions.