Dropbox may not natively add client side encryption in the near future. The way Dropbox has stored data from the beginning is by deduplicating information across all its users to save space. So if you upload a book or a movie or a song and I upload the same, Dropbox stores one single copy of it for the both of us.
This is just a simplified explanation. The actual deduplication is done in smaller blocks.
If you want client side encryption with Dropbox, you have to add a layer before the Dropbox client sees your files on your system, using Cryptomator or Boxcryptor or encrypted volumes with Veracrypt, etc.
Or you could switch to other online backup/sync services that claim to have client side encryption, like SpiderOak and a few others.
This is just a simplified explanation. The actual deduplication is done in smaller blocks.
If you want client side encryption with Dropbox, you have to add a layer before the Dropbox client sees your files on your system, using Cryptomator or Boxcryptor or encrypted volumes with Veracrypt, etc.
Or you could switch to other online backup/sync services that claim to have client side encryption, like SpiderOak and a few others.