upcoming network outage 2023-01-31

[Jon Turney]

We've received word from our data centre hosts that they will have a 
network infrastructure outage 2023-01-31 (this coming Tuesday), 
8am-12am-ish EST (UTC-5).

cygwin.com web and git will be unavailable during this outage.

The Cygwin setup program should continue to function (as if it can't 
contact cygwin.com, it should use a cached mirror list, and all package 
downloads are from a mirror).