Nightly users being switched to new AUS on Monday, September 30th.
On Monday, September 30th I will be landing the necessary changes to switch our Nightly (and nightly-based) users to the new update server at aus4.mozilla.org. Nightlies from mozilla-central will be respun to ship out these changes as soon as possible, so there will be new updates available for users mid-day EST. For more details see my previous post on the topic.