In 1992, copyright laws were amended making renewals automatic and renewal registration optional for any work that was originally copyrighted between the dates of January 1, 1964 and December 31, 1977. For works before these dates, the copyright must have been renewed in order to continue to have copyright protection.How can the answer be improved? copyright renewal
The period from is of special interest for US copyrights, as works published after January 1, 1964 had their copyrights automatically renewed by statute, and works published before 1923 have generally fallen into the public domain. Between those dates, determining whether a work's registration was renewed as required has been a challenge.