OIT module in Exchange Server is replaced by DocParser

Summary 

Starting in Microsoft Exchange Server 2019 CU15, Exchange Server uses DocParser as a replacement for the "Oracle Outside In Technology" (also known as OutsideInModule or OIT) to perform text extraction workloads when it processes email messages in transport if those messages contain attachments.

DocParser is a Microsoft library that's designed to parse various file formats. For supported file types, see the following Learn article: Use transport rules to inspect message attachments.

Microsoft is providing a PowerShell script for administrators to use if they want to override the default setting that replaces OIT. The script enables OIT despite the update’s restrictions. For the script and detailed instructions for its use, see the following CSS-Exchange Blog article: ConfigureFipFsTextExtractionOverrides. 

Resolution

To fix this issue, install the following cumulative update: 

• Cumulative Update 15 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019

More information 

If you encounter scenarios that are not described here but that are affected by the OutsideInModule replacement, you can contact the Exchange Server team at <ExchOnPremFeedback[at]microsoft.com>.