Microsoft 365 eDiscovery features will respect documented limits from May 10. The changes are likely made to conserve resources consumed by searches against the massive amounts of data now found in Office 365 tenants. The changes probably won’t affect eDiscovery investigators except in reminding everyone that the items shown in search preview are only a representative sample of what can be found by a full search.
Microsoft announced the retirement of legacy eDiscovery tools from Office 365. The Exchange Online in-place holds and eDiscovery tool, Office 365 Advanced eDiscovery 1, and the Search-Mailbox cmdlet are being retired. All will be gone by mid-2020. It’s a pity to see the Search-Mailbox cmdlet being removed, but time and progress make this kind of thing inevitable.