Is there somewhere a script that can do a restore backup file "with oids" in some newer DB where there is no term "with oids"?
Short answer: No!
Long answer: try use the pg_dump binary from your new version (12) connecting to your old version... is the best practice when you want to upgrade your PostgreSQL using dump/restore strategy.
Regards,
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Fabrízio de Royes Mello Timbira - http://www.timbira.com.br/ PostgreSQL: Consultoria, Desenvolvimento, Suporte 24x7 e Treinamento