Attestation Approval by E-mail Reply (Exchange Online)

Question

I located the following technical document regarding attestation by e-mail responses, however I'm curious to know if this is possible in environments that do not have on premise Exchange, but have Exchange Online that is synchronized to AD without Identity Manager. 
 https://support.oneidentity.com/technical-documents/identity-manager/7.1.1/attestation-administration-guide/32#TOPIC-659001 
 The ideal scenario is that approvers are able to respond to an attestation request by e-mail on their mobiles, and to avoid the need for authentication within the internal network. 
 If this is not possible, are there any other recommended methods to approve or deny attestations without requiring the approver to located on the internal network?

Markus Weiss-Ehlers · Accepted Answer

The approval by mail feature uses the Exchange WebServices to monitor a mailbox, where the approval mails are send to as described in the manual section. 
 I do not know if this works with Exchange Online as well if you specify a proper Exchange Webservice URL. 
 But if not, you can override the ootb script VI_MailApproval_ProcessInBox that is processing the approval mails.

VilounV · Answer

Did you look at the configurations from this post? 
 https://www.quest.com/community/products/one-identity/f/identity-manager/20161/approval-by-mail-through-an-o365-mailbox 
 Also, one thing I did noticed is that o365 must of changed something because you will have to make a minor tweak. 
 1. Change the code to create the EWS to use Exchange2013_SP1 for " VI_MailApproval_ProcessInBox " 
 Old: 
 Dim ews As New ExchangeService(Microsoft.Exchange.WebServices.Data.ExchangeVersion.Exchange2007_SP1) 
 New: 
 Dim ews As New ExchangeService(Microsoft.Exchange.WebServices.Data.ExchangeVersion.Exchange2013_SP1) 
 Probably better if you coded it as switch so that you can go between On-Prem and Office 365. 
 
 Since we are changing that code, that means you must change the "process orchestration" that calls the ootb, which is called " VI_ITShop_Process Approval Inbox ". 
 
 After that, all should work fine if you configure the configuration settings and create the approval workflows to use approval by mail.