https://www.icyphoenix.com/viewtopic.php?f=2&t=9609&p=60873#p60873
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Informpro
Mon 05 Sep, 2016 23:45

Re: Integramod And Icy Phoenix Questions
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[code]UPDATE phpbb_forums SET parent_id = 84 WHERE id = 13;[/code]

Please try this SQL query after the conversion, just before clearing cache.