As posted on the CRA Website:
"File by May 5 and incur no penalties or interest
On April 24, the CRA issued a communication to some Canadians that referred to an incorrect filing deadline for 2014 tax returns of May 5, 2015, rather than April 30, 2015.
The CRA takes full responsibility for the error and our first priority is to ensure that no Canadian is negatively affected.
As a result, and at Minister Findlay's request, 2014 tax returns filed by midnight on May 5, 2015, will not incur interest or penalties.
The CRA sincerely regrets and apologizes for any confusion this may have caused."