In yesterday’s rollup article for December 2014, Microsoft mentioned that they have upped the 25MB message size limit to 150MB when onboarding a mailbox to Office 365. The new limit applies, for instance, to mailboxes moved through a hybrid configuration to Office 365:

Office 365 Exchange Online message size onboarding limit increase — We are making a change to allow customers to migrate larger mail messages to Exchange Online. We now allow messages up to 150MB to be migrated to the service. The change is available immediately to all customers and is published as a new limit in the Exchange Online limits page in the Office 365 service description. We are not changing other limits such as mailbox size or maximum send/receive limit for messages. This change enables customers with large messages to easily migrate their existing content to the message.

Before, any message greater than 25MB were skipped. The hard limit might have been a little over 25MB, because the system accounted for overhead as well. As a result of that, the administrator either had to manually export those message from the mailbox (to keep them) or just ‘leave them behind’.

According to Paul Cunningham (ExchangeServerPro.com) this change also applies to offboarding scenarios.

This new limit is without any doubt good news for many organizations that are moving (or looking to move) to Office 365. The change also adds something extra to consider when onboarding mailboxes –mainly with regards to the velocity of a migration. Before, mailboxes could potentially be a lot smaller if it contained many items that exceeded the limit. With the new limit, administrators will have to take into account the additional payload (size) of those messages; potentially increasing the amount of data that has to be moved to ‘the cloud’.

All in all, this is yet another obstacle that Microsoft got rid of in favor of moving to Office 365 easier, but there are still some ‘limitations’ left; I can’t wait for Microsoft to address those too! For instance, the message size limit for sending and receiving messages hasn’t changed and Free/Busy lookups between two hybrid organizations is still a pain as well. However, I have no doubt that Microsoft will tackle these issues in due time as well.