---
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"@type": TechArticle
"@id": https://www.twilio.com/docs/conversation-intelligence-classic/limitations#article
headline: Limitations
description: ""
url: https://www.twilio.com/docs/conversation-intelligence-classic/limitations
inLanguage: en
dateModified: 2026-06-25T22:35:25.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# Limitations

## General Limitations and Caveats

* Conversation Intelligence (classic) is not PCI or HIPAA compliant.
* Encrypted recordings and recordings of PCI enabled accounts are not supported.
* Twilio Recordings with external storage are only accepted using the `MediaUrl` on the Transcript creation.

## Transcripts App

* In past pre-release documentation, the Transcripts App was called Discovery. The old name is still used in some places, such as app retrieval URLs.
* Transcripts are indexed and available for search for 90 days.
* Search terms are linked with the OR operator. For example, `macaroni salad` will match transcripts that have `macaroni` OR `salad`.

## Transcription

* PII redaction is only available in `en-US`.
* The following limitations apply when fetching media stored in a third-party location (specified by a `MediaUrl`).

  * Conversation Intelligence (classic) does not send an `X-Twilio-Signature` header for media fetch requests. As a result, media stored in Twilio Assets needs to be made public.
  * If you use external recordings, Basic authentication on `MediaUrl`s is not supported. If you store the recordings on S3, use a [presigned URL](https://docs.aws.amazon.com/AmazonS3/latest/userguide/ShareObjectPreSignedURL.html). And when storing them on Azure Blob Storage, use a [Shared Access Signature (SAS)](https://docs.microsoft.com/en-us/rest/api/storageservices/delegate-access-with-shared-access-signature).
  * `MediaUrl`s that respond with a HTTP status code that is not a 200 will result in a transcription request that does not complete.
  * Requests to fetch third-party media are performed exactly once. There is no retry behavior.
* Conversation Intelligence (classic) does not perform speaker diarization on recordings. The use of mono recordings will result in lower transcription accuracy.
* Recordings that are under two seconds in length are not transcribed.
* Only up to two Participants can be overridden in the Channel object of the Transcript resource.
* Conversation Intelligence (classic) will only process recordings or 3rd party media that are under 3GB.

## Language Operators

* [Prebuilt Language Operators](/docs/conversation-intelligence-classic/pre-built-operators) cannot be run on a specific channel of a recording.

## Transcription Viewer

* In past pre-release documentation, Transcription Viewer was called Annotator or Conversation Viewer. The old name is still used in some places, such as app retrieval URLs.