Enable update-AddressList in Offfice 365
New address lists aren't automatically updated in Exchange Online. Additionally, the Update-AddressList and Update-GlobalAddressList cmdlets aren't currently available in Exchange Online. This behavior is by design.
After you create the address list, make a change to each object that the recipient filter applies to. To do this, use one of the following procedures, as appropriate for your situation.
If you have an on-premises and cloud environment that's using Active Directory synchronization
1.Set or change an attribute for all users in the local installation of Active Directory Domain Services (AD DS) who correspond to the filter objects. For example, specify a value for the CustomAttribute1 parameter. To do this, follow these steps:1.Open the Exchange Management Shell.
2.Run the following commands. The following set of commands specifies a value of "temp value" for the CustomAttribute1 parameter.
$mbxs = Get-Mailbox –ResultSize Unlimited
$RemoteMBX = Get-RemoteMailbox –ResultSize Unlimited
$mbxs | Set-Mailbox –CustomAttribute1 “temp value”
$RemoteMBX | Set-RemoteMailbox –CustomAttribute1 “temp value”
The workaround is pretty time consuming in a large organization, so I suggest enabling update address list feature, like in exchange Server
Dros M commented
This is a feature that is desperately needed in some way shape or form. Modifying AD Objects like this is a poor solution because now every account touched shows that an admin as modified an account leading to a very long audit log to explain.
Jakob Nøtseth commented
Please, important for any larger organization
We need this feature