Is MailStream Plus 8.3.2 a required release

Per the 8.3.2 Release Notes, (which will be available at the time the software is released)-
Is this release mandatory?
No, this release is not mandatory. However, if you are currently using release 8.3.0, you must update to 8.3.1 or 8.3.2, as July 2016 will be the last postal reference file for release 8.3.0.

(Note the July Reference files will be valid for mailings starting August 1 thru Sept 30 2016. )
UPDATED:  April 10, 2017