47 CFR § 61.16
Base documents
February 16, 2021
(a) The Base Document is a complete tariff which incorporates all effective revisions, as of the last day of the preceding month. The Base Document should be submitted with a cover letter as specified in §61.15(i) and identified as the Monthly Updated Base Document.
(b) If there have been revisions that became effective up to and including the last day of the preceding month, a new Base Document must be submitted within the first five business days of the current month that will incorporate those revisions.
[76 FR 43211, July 20, 2011]