On the site of Penguin daughter Gütersloher Verlagshaus, the German publisher of Hallo!, a review was published by reviewer Sabrina. This is an English translation:

Helping children understand refugees and the reasons they flee – especially for children who mostly have everything – is very difficult. I therefore find books like this one very useful. Even if the beginning is very sad and I don’t want to expose my children to such things, I think it’s important that they know that not all children are doing so well. On the one hand they should appreciate our “Western prosperity” and on the other hand be open-minded. The illustrations are great. Even though the first double page spread where the mom leaves with the three kids is sad, it gets better with each page. Helping hands and warm beds bring the family a little closer to safety – until they arrive at their new home at the end. The short text on each page is definitely hopeful and understandable for children. A really great children’s book that points out grievances, shows that not everyone is equally well off, and yet also shows how the tide can turn if everyone lends a hand to help and acts with kindness!

Here is the complete review in German.