in force on July 10, 1974. These changes concerned the introduction of special advantages for developing countries and the explicit acknowledgment of an author's exclusive rights to reproduction, performance, and broadcast of a work.Universal Copyright Convention (1971), article IVbis. The UCC was designed to demand less stringent copyright requirements than the Berne Convention with the goal of achieving international copyright recognition for countries that considered the Berne Convention too demanding. The UCC required a minimum general copyright term of 25 years p.m.a. or, for works where copyright began upon the publication, of 25 years since the first publication. Shorter durations were allowed for a few kinds of works. The UCC gave signatory countries more leeway than the Berne Convention to keep the idiosyncrasies of their laws (such as requirements for copyright registrations, or a two-term scheme as it was used until 1978 in the United States). The UCC applied only to works that were not permanently in the public domain in the country where copyright was claimed. The provisions of the Berne Convention supersede those of the UCC in countries that are signatories of both treaties. Of all the signatory countries of the UCC by 2006, only Laos was not also a signatory of the Berne Convention. On February 27, 1973, the Soviet Union joined the Geneva version of 1952 of the Universal Copyright Convention (UCC). The UCC became effective in the USSR on May 27, 1973. Until then, the USSR had not participated in any multilateral international copyright treaties; it had only concluded two bilateral contracts with Hungary (in 1967) and Bulgaria (in 1971). The USSR timed its accession to the UCC to occur before the 1971 Paris version of the UCC entered into force. Once the Paris version had become effective, accessions to the earlier Geneva version were no longer possible. The USSR would then have been forced to implement the somewhat stronger provisions of the 1971 Paris version, which in particular explicitly recognized an author's exclusive rights to reproduction, performance, and broadcast of a work. By virtue of the UCC, foreign works first published after May 27, 1973 outside of the USSR became copyrighted in the Soviet Union if the author was a national of any other signatory country of the UCC, irrespective of where this publication occurred, or if the work was first published in any other UCC country, regardless of the nationality of the author.