The Data Loss Prevention (DLP) feature in Microsoft Exchange Server 2019 and Microsoft Exchange Server 2016 doesn’t detect Chinese Resident Identity Card numbers correctly if the last digit (checksum) is an ”X” character. This issue occurs because “X” is also the Roman numeral for 10. 

This issue occurs if DLP encounters a number such as the following example:

  • 110102YYYYMMDD888X

Note In this example, <YYYYMMDD> represents the actual date of birth.


To fix this issue, install the following updates, as appropriate:

Cumulative Update 12 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019

Cumulative Update 23 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016

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