If you plan to change your phone you can easily move your karma and all your Jodels to your new device.
First thing when you change your phone is to make sure that you back up your present data. Just on your old phone create a Backup of your Jodel as described here: https://jodel.zendesk.com/hc/en-us/articles/360001021773
Now, on your new phone, first log in to your iCloud/Google account and then install Jodel. On opening the Jodel app you should see all your previous data.
If all worked fine, remember to do a factory reset of your old phone. This way you ensure that the person who gets your phone will not be able to see your previous jodels.