Advanced folders are available only for Sync Pro.
There is no way to UPGRADE Standard folders to Advanced folders due to significant differences in their architecture. If you would like to share data using Advanced folder functionality, all you have to do is remove Standard folders from Sync and re-add them as Advanced folders (available in Sync Pro only).
STEPS TO TAKE:
1. Disconnect 1.4 folders which you'd like to upgrade (Options > Disconnect):
Also, you can re-add the file by dragging it from the file browser into the Sync window (not available on Linux or WebUI), or by starting with the “Add folder” button in the top left hand corner of Sync.
4. When the folder is done re-indexing, it will automatically appear on all your linked devices. You will have to send a new link to any other users you want to share it with.