LOADING EXISTING DATA WITH ECHO

Hello, I need your help. I have a server with a PostgreSQL database. Now I have written an APP for mobile devices with Aurelius and Echo and use SQLite.
As long as I create new data on the server, it will also arrive at the mobile device. Echo works great!
But how do I get data on the mobile device that I collected BEFORE installing the APP?
If I download this data directly from the server during the APP installation, before I start Echo, the Echo server stops and I have to delete and recreate the Echo files on the server as well as on all end devices. I think if I write data bypassing Echo on the direct way to the mobile database, then indexes are no longer correct and Echo stops. But how else do I transfer existing data that I need on the mobile device?
I can't find anything about this in the documentation.

Thx for any help!

Echo replicates data that is created after it starts logging all changes to the database. Unfortunately it doesn't have any mechanism to replicate data modified before the logging starts. That should be up to your application.