Hi

Currently migrating Exchange 2010 to 2013. Randomly receiving this bounce message.

Remote Server returned '554 5.2.0 STOREDRV.Deliver.Exception:NotSupportedWithServerVersionException; Failed to process message due to a permanent exception with message The mailbox of user xxx@yyy.com that is located on a server that is running version 14 can't be opened on a server that is running version 15. 

Any idea what may be causing this?

Thanks

Hi

is this happening when you are moving the mailbox from 2010 to 2013 or when the mailbox is on 2013?

Hi,

When will users receive this NDR? I have seen the same issue when uses sent emails to migrated users in distribution list and worked fine if users sent to user directly.

Are  Exchange 2010 and Exchange 2013 on the same domain controller?

Did you move the arbitration mailboxes from Exchange 2010 to 2013? You can check this by the following command

Get-mailbox -arbitration | fl name,Displayname,database

Best Regards.