CIRA, the .ca registry, is taking their entire registry offline except for resolution services for 24 hours.
While most domain registries conduct scheduled maintenance that would impact the SRS at some level and for several hours at a time I don’t think I’ve ever seen a relatively large domain registry plan a 24 hour outage before.
You can read details of the outage on CIRA’s site.
There are a LOT of issues with such a long outage, but what I find decidedly odd is that they would schedule something like this on a weekday when the bulk of transactions (registrations / renewals / transfers) take place.
Effectively this outage means that all activity in .ca will be frozen for 24 hours. Odd and if you were active in .ca, very frustrating.