:phew: where to start?
what about: search-function is your friend? 
it would tell you that due to some problems in a 3rd-party-piece of sh… errrr software delivery of NC 12.0.0 to stable-channel was stopped. problems should be solved with NC 12.0.1
and take a look here to find who soon it’s gonna come - the FAQ about when will 12.0.1 be released… ;o)
→ [FAQ] When will 12.0.1 be released?
hope that’ll help a bit
cheers