Hello,
I've downloaded and installed v2.5.2 on my site and found that using admin panel gives me 404 errors in logs. There is one file that is for sure the cause of that: iv-admin/assets/js/imagevue.upload.js
It seems that you've moved the most of static files to assets directory but forgot to update this file (maybe also some others). All references to 'images' folder should be updated to 'assets/images' and the file should look like the one i've attached
Regards,
JobTitle