Effect of Designated Days on Patent and Patent Application Maintenance Fee Due Dates, and Courtesy Deemed Expired Letters

The purpose of this notice is to clarify the effect of the designated days on due dates, prescribed time limits, and courtesy letters; and, to inform the applicant or patentee of a system and correspondence error resulting from the designated days.

The Commissioner extended deadlines under subsection 78(1) of the Patent Act in relation to designated days under subsection 78(2) of the Patent Act. During the designated days of to (inclusively), the time to take an action with respect to business before the Patent Office was extended to the next day that was neither a prescribed nor a designated day. This date was the first business day after this continuous period of designated and prescribed days, .

Effect of the designated days on Maintenance Fee Due Dates

All applications or patents whose maintenance fee due date fell within the Designated Days period now have a 2020 maintenance fees due date of . Designated Days have no impact on maintenance fee due dates that fall on or after . In addition, the original filing date must be used to determine subsequent maintenance fee due dates; these will fall on the anniversary of the original filing date.

Effect on deemed abandonment for failure to pay a Maintenance Fee (patent applications)

All applications whose maintenance fee due date was on or before , and whose date of deemed abandonment fell within the Designated Days period, now have as their date of deemed abandonment. The reinstatement period of 12 months for these applications ends on .

Effect on deemed expiry for failure to pay a Maintenance Fee (patents)

Some patents had a date of deemed expiry on or before . For those patents for which the six month period after that date of deemed expiry fell within the Designated Days period, the start date for the period in which to reverse deemed expiry is now 12 months from .

Courtesy Deemed Expired Letters affected by Designated Days

Because of a temporary system error which has since been corrected, the Office has sent some courtesy letters titled Patent Term Deemed Expired omitting the date of deemed expiry or indicating an incorrect date of deemed expiry. The date of deemed expiry is the date the prescribed maintenance fee was originally due. That date of deemed expiry, if it fell on a day prior to the designated days, is unchanged and not subject to any adjustment. The date from which to calculate the reversal of deemed expiry for these patents is the date of deemed expiry. However, if the six month time period provided for in the Patent Act and Rules after the date of deemed expiry fell within the designated days, the date to calculate the reversal of the deemed expiry is extended to and the time period to reverse the deemed expiry is 12 months from .

It can be difficult for clients to determine the correct date of deemed expiry. Therefore, the Office has identified patents impacted by this issue and will reprint these courtesy letters.


Courtesy letters are intended to provide information only, and the authority to prescribe any and all required actions rests entirely in the Patent Act and Rules. Actions required by the Patent Office are communicated by Notice and Requisition. Applicants, patentees, and their representatives are reminded that they are wholly responsible for meeting all prescribed actions or payments by their prescribed dates or by the calculation of those prescribed dates.