How to know what the Perpetual flag on the license does using MailStream Plus, MAIL360 Server, and MAIL360 Data Manager

-MailStream Plus (and this applies to the subcomponents: Palletization Plus, Manifest Reporting Plus, and DuoSort.)
-MAIL360 Server
-MAIL360 Data Manager
(FYI- As-of the current 2.4.0 version of *MAIL360 Manager*, licensing is not used.  Mail360 Manager is a different application than MAIL360 Data Manager.)
When you run a license report for the one of the products listed, in the indented section there is a line : License Expiration Date”.  That line will either have an Expiration Date there, or the word “Perpetual”. 

Client ID: 000000000000001
Group 1 Software                        Group 1 Software Inc.
4200 Parliament Pl Ste 600              4200 Parliament Place Suite 600
Lanham MD 20706-1882                    Lanham Maryland  20706-1844
United States
ATTN: Adam Collinson
6309072595                              Phone: 888-413-6763
   Product: MU
   Today's Date: 04/24/2017
   Original License Date: 03/03/2003
   License Expiration Date: Perpetual
   Maximum Number of Transactions: unlimited
   To be used between: 03/03/2009 through 12/31/2015
   Date of Last Run: 04/23/2017
Total number of transactions for last run:             78
Total number of transactions since 03/03/2009  15,475,486    0.00% of Limit

If it says “Perpetual” as shown above then the software will *not* stop working due to an expiration date.
FYI- Two lines below that is a line ‘To be used between:’.  That line just reflects the contract period, and not a license expiration date.  
In fact when the 'to be used between' end date is passed, the next time a job is ran the Perpetual status of the license will automatically cause the ‘To be used between:’ end date to be extended for another year.
For more information about loading, using, and running reports on license files, please see the ‘License Management Guide” available on the web site.
Environment Details
Products affected:  MailStream Plus Mail360 Data Manager Mail360 Server , All Platforms
UPDATED:  April 21, 2017