Mojibake repair, not a rename. The stored name was "Mario JoA£o Alves" (with the UTF-8 bytes of "ao" double-encoded through Latin-1); the singer is the Portuguese tenor Mario Joao Alves. Corrected to the correct UTF-8 spelling. Source: the Fonoteca Municipal de Lisboa catalogue record for the Teatro Nacional de Sao Carlos programme of La donna del lago, 27 February and 1 and 4 March 2005, which spells him "Mario Joao Alves (Serano, Bertram)" -- http://web.archive.org/web/20250222134332/https://fonoteca.cm-lisboa.pt/cgi-bin/info3.pl?4655&BIB&1 Found while filing that performance as recording 12266. Only the encoding changed; the first name still reads Mario Joao and the surname Alves.

Migration: a zero year, month, day or OperaClass id meant the value was unknown, not that it was zero. Set to null.