I've just started using sync-1.5 with a self-hosted FXA stack, and notice that when I alter the "What to sync" settings on one client, that selection itself is synced to another client (both clients are FF37 Desktop on amd64 Linux). Under sync-1.1, each client kept its own copy of these settings. This was valuable to me as I wanted all my clients sharing bookmarks, but only my desktop clients sharing history, not my mobile client (to save on data allowance and power). Another example could be passwords, where you might not want all your linked clients to be "trusted" with access to them via sync. Different device classes will have different roles in the life of the account-holder, so it follows that the desired set of synced features may differ accordingly. Therefore I suggest that the selection should be per-client, as in sync-1.1. I'm aware that some work is underway on updating this component at the moment, so I hope this is a timely interjection.

Need to find the dupe.

(In reply to Robin Bankhead from comment #0) > I've just started using sync-1.5 with a self-hosted FXA stack, and notice > that when I alter the "What to sync" settings on one client, that selection > itself is synced to another client (both clients are FF37 Desktop on amd64 > Linux). > > Under sync-1.1, each client kept its own copy of these settings. This has been duped, but I want to correct mis-information for viewers at home: this is not true. All Firefox Sync implementations that I am aware of share a single set of "enabled/disabled Sync engine" flags across all devices in a device constellation.