Any further updates on the rollout? I seem to have it on all our first release tenants on the web, and in the Windows 10 Mail app the availability is inconsistent.
On two PCs that have the same Mail version the specific accounts that support it are random - For example I have Account A and Account B - They both have Focussed Inbox on the web.
On PC A, W10 Mail allows me to turn on focussed Inbox for Account A
On PC B, W10 Mail does NOT allow me to turn on focussed Inbox for Account A
On PC B, focussed inbox is only allowed to be turned on for Account B, but not A
To me this says both fully support it server side, and both clients absolutely support it - So how come we can't have it consistent across devices? Is this a bug, a known issue with the rollout or something else?