I really need an app where you can sync files between devices.

Not cloud storage, just an app where you "link" the file you wanna sync and choose which devices need it and then it syncs the files between every time it changes. Like the files are stored localy but will sync when internet is available (maybe even with a buffer that keeps one version back of the file you sync on the device it gets syncd to.

There are files I want to be accessible while offline but also want to have them up to date.

The struggle is real.

Mango