CRA accepts that where a return filing deadline falls on a Saturday, the deadline for related forms also is extended to the Monday

CRA considers that Saturdays are "public holidays" as defined in the Interpretation Act. Among other things, this means that if the return filing deadline of the taxpayer falls on a Saturday (e.g., Saturday, April 30, 2016), the filing deadline for related forms to be filed by that deadline (e.g., Forms T2057, T1134 and T5013) will be extended to the following Monday.

Summary of Q. 21 of 9 October 2015 APFF Roundtable under 2015 APFF Conference.