Many people are finding that they cannot see how much whitespace they have anymore. 1221 events simply do not show up in the Application Log anymore.
Well the good news is this is by design, with the replacement of OLD with OLD2.
You can now see the status of your whitespace via Powershell:
Get-MailboxDatabase YourDatabaseHere -Status FL AvailableNewMailboxSpace
Note the difference between using FL and Select after piping
MVP - Exchange Server