With Exchange Server and Exchange Online, Microsoft enables organizations to immutably preserve mailbox items for discovery using an in-place strategy, keeping those items within the Exchange infrastructure. The technology used to achieve immutability with Exchange is different than sending items to a separate, read-only archive. The Exchange approach achieves the same or better results—preserving all inbox data in a way that is tamper-proof and discoverable—while at the same time conserving more of the relevant data, reducing IT complexity, and delivering a seamless user experience.
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