Seville and St Petersburg are replacing Dublin and Bilbao as Euro 2020 venues.
UEFA's executive committee was meeting on Friday to finalise plans after Bilbao and Dublin could not guarantee fan presence at matches.
"Seville and San Petersburg - officially" tweeted Boniek, "There is a bit of work ahead of us, we start over, camp, journeys, all logistics".
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Boniek is an official of the Polish FA and Poland were due to play games in Dublin and Bilbao.
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