Indicate that users *can* skip 1.2.2.
A manual upgrade is required for 1.2.2.
Make the change more about "upgrade checking".

Especially since we don't provide an incremental upgrade.
Simplify announcement for 1.2.2

All users will have to do a manual upgraed, either to 1.2.2 or to 1.2.3.
So let's encourage them to do it for 1.2.2: this will save them error
messages after January 3rd and save us some user support.
Adjust date
It's ok to wait for 1.2.3