The first thing these articles must mention is in which nightly SPECIFICALLY will the switch be made. Because it didn't happen yet with the latest nightly, and (the PR that will flip the switch is not even merged yet ):

-Zpolonius=off

error: incorrect value `off` for unstable option `polonius` - either no value or `legacy` (the default), or `next` was expected

Also

NLL's analysis is flow-insensitive.

Polonius Alpha passes this because its analysis is flow-sensitive

Always ask two+ people to proof-read your announcements before hitting publish.