GUI customizations in the bottom bar


I am conducting a seafile upgrade from version 6.3.4 to version 7.0.5.
In the previous version, I made some GUI customizations in order to add more links to the bottom

I did this by creating a folder (seafile/seahub-data/custom/templates) and add the changes in nav_footer.html.

After the upgrade, those customizations disappeared. After some researchs I found that the software is not working like before therefore this method is no longer valid.
I figured out then in Seafile 7, I need to manipulate the JavaScript code. This is more complicated than before. I agree, but it is possible.
I will be grateful if I receive any help.
Best regards