No, must have been something else. I saved the changed files and tested right away, so any outage caused by upgrade would have been a minute at most.
However, I've had some problems with stability since upgrading server earlier in the year. The php module seems to hang in IIS8 and I could never figure out why. I had to create a scheduled task to restart IIS once a day, so if it does hang the forum comes back to life automatically within 24 hours.