bytea problems

Hi,

I have an old Java-app that was developed a long time ago, it was written for Postgres version 8.

I have exported the DB from that old server and imported into a Postgres11 server.

Almost everything seems to work. Except when my app tries to fetch jpeg files stored in the DB as bytea.
The files I retrieve are unreadable. But when I look att the pictures in Postico they look good & I can save them and open them with other applications.

I can add new pictures to the DB using the old app, they also works in Postico, but not when my app tries to read them back.

Any hints? Have the way bytea data is selected changed? Should I try to select with some kind of decode function?

Regards,
Lars.