I recently did a copy of data between 188.8.131.52 and 184.108.40.206 and in the past I had done between 9.3.1 and 220.127.116.11. So, based on experience and not actual testing, you should not have any issues as long as you check the header of each journal.
I assume that you can create a SR to Oracle to get specific answer or write the same question in the HFM (MOSC)
If you just did an upgrade, everything should work fine or at least you should be able to change it easily. There were no big changes for journals between 9.3.1 and 18.104.22.168.
If you did increase the number of dimensions and or renamed some of them, than you might face bigger changes.