37 C.F.R. § 2.162 Notice to registrant.
Title 37 - Patents, Trademarks, and Copyrights
When a certificate of registration is originally issued, the Office includes a notice of the requirement for filing the affidavit or declaration of use or excusable nonuse under section 8 of the Act. However the affidavit or declaration must be filed within the time period required by section 8 of the Act even if this notice is not received. [64 FR 48925, Sept. 8, 1999]
Title 37: Patents, Trademarks, and Copyrights
PART 2—RULES OF PRACTICE IN TRADEMARK CASES
Cancellation for Failure To File Affidavit or Declaration During Sixth Year
§ 2.162 Notice to registrant.

