+ within the last (28th) calendar year of the original term of copyright
or
+ at any time during the renewed and extended term of 67 years.

To determine the filing period for renewal during the original term:

1. First, determine the date of original copyright for the work. (In the
case of works originally registered in unpublished form, copyright began
on the date of registration; for published works, copyright began on the
date of first publication with copyright notice.)

2. Then add 28 years to the year the work was originally copyrighted.

This will determine the calendar year during which the copyright becomes
eligible for renewal with a renewal filing during the original term due
by December 31 of that year. An exception to this rule exists when the
copyright notice in the work contains a year date earlier than the year
date of first publication. In this case, the renewal filing period is
computed from the year date in the copyright notice. For example, a work
published January 20, 1975, contains a copyright notice reading
"Copyright 1974 by Anderson Homes." Compute the 28-year original term
from the year 1974.

To renew a copyright during the original copyright term, the renewal
application and fee must be received in the Copyright Office during the
28th year of the original term of copyright. All terms of original
copyright run through the end of the 28th calendar year making the period
for renewal registration in the original term from December 31 of the
27th year of the copyright through December 31 of the following year.