Looks like GST/HST return processing will also be delayed, especially if you file close to or after March 19th. CRA is going to be replacing their current GST/HST system from March 19th to April 9, 2007 (3 weeks!). There’s definitely going to be a service interruption.
This does not mean you can file your return later or put off payments, though. The new failure to file penalty is
1% of the amount unpaid or outstanding for the reporting period as of the return due date, plus 0.25% of the overdue amount times the number of complete months the return was overdue, to a maximum of 12 moths.