Can anyone explain me in a few sentences, usage scenarios and ideas that PM's/engineers from Symantec had in mind when developing Enterprise Vault Office Mail App. Is it a supplement to full blown Outlook add-in, is it meant as a long term replacement for it or something else?
What are your usage scenarios for Enterprise Vault Office Mail App?
The obvious use case is for Outlook Web Access. Since users viewing their mailbox in a browser won't have our Outlook Add-in available, the Office Mail App allows these users to interact with EV archived items.
It can replace some of the Outlook Add-in's functionality, which might be suitable in certain use cases where only limited functionality is required (e.g., thin clients with no need for Vault Cache or Virtual Vault). However, it was certainly not conceived as, nor is it moving towards, a full replacement for the more robust Outlook Addin.
Chris is absolutely right. To elaborate a little more:
In OWA for Exchange 2007/2010, EV had our "OWA Extensions," which were installed on the CAS and allowed users of those mailboxes to access EV toolbar functions in OWA (2007/2010).
The OfficeMailApp is the ONLY OWA option for 2013 and 2016 and after for users to access EV Toolbar functionality. Those old OWA extensions won't fly on a CAS anymore, as that role has changed in Exchange so drastically.
It's just an added side-effect/bonus that due to changes in Outlook in 2013 and after that it works in Outlook too.
So think of it as the only OWA option for EV in 2013 and after, and you could also choose to use it in Outlook if you so desire.