Travel document for a child

[stranger09]

Since very recently we noticed that my 4 y.o. kid's passport were expired (I know how careless we are... ) and managed to get him a new one.

In the old passport he has a valid Finnish residence permit sticker for another two years.
We are currently outside EU zone, and about to travel back to Finland very soon, it seems that we don't have time to get the sticker moved to a new passport.
Will it be a problem for my kid to enter, in case we show his both old and new passport? (My wife and I are both Finnish PR holder.)

Anyone has similar experiences?
I would be very appreciate your comments!

[Rip]

Literally entering Finland should not be too much problem - after all if questions arise, they should be able to check you have a valid permit (even if the physical document is not quite up to date). I'd think if there are more serious problems, they would be earlier: first at the airline check-in desk, then when you're entering Schengen area, if it does not happen on Helsinki airport. What is your travel route and nationality?

[Pursuivant]

You have the old passport with the sticker with?

It might be more a problem in the "schengen border" as the Finnis computer system udually works