If it is a Birdy World 2 as it seems to be, its part of the Birdy 3 range and there are no risk of frame (actually rear swing arm) crack.

You might want to upgrade to the latest chain tensionner placed around the bottom bracket because with the tensionner added to the derailleur cage like on Birdy 1 and Birdy 2, there can be chain derailling while unfolding the bike.