After upgrade to version 188.8.131.521 Microsoft Exchange logs no longer get truncated. In the Windows Application event logs you might get an error with an event ID 2034.
This is a known issue in build 184.108.40.2061. If you disable Microsoft SQL logs truncation in Job properties then Microsoft Exchange logs truncation will be disabled too.
Exchange logs truncation is regulated by a single boolean when you call SetBackupSucceeded() WinAPI with Exchange VSS writer writerID.
When that boolean is set to true Exchange VSS writer goes ahead and truncates the logs, and v220.127.116.111 sets this boolean to false based on SQL configuration in Job properties.
Enable SQL log truncation in Job properties and this will allow Exchange logs to be truncated.