> For a complete page index, fetch https://docs.synthflow.ai/llms.txt. For full documentation content, fetch https://docs.synthflow.ai/llms-full.txt.

# Changelog

## October 2, 2026

## Actions API: Readable names

Names of call transfer, post-call SMS, in-call SMS, and WhatsApp actions are now saved exactly as you type them, up to 64 characters, through both the [Actions API](/api-reference/platform-api/actions/create-action) and the app.

## Agents API: Updated Get an agent response

The [Get an agent](/api-reference/platform-api/agents/get-assistant) response now includes these fields:

* `knowledge_base_id`
* `agent.greeting_message_mode`
* `agent.greeting_message_human_talk_timeout`
* `agent.suppression_level`
* `agent.redact_pii`
* `agent.voice_style`, now returned as a decimal instead of `0`

## October 1, 2026

## Improved performance in Logs search

Searching your logs is now much faster, including in high-volume workspaces.

* **Call logs:** The **Phone Number** filter now only finds exact matches, so results load instantly. Enter the full number, including the country code.
* **Webhook logs:** Search by a full Call ID, webhook log ID, or action ID for instant results.

## September 29, 2026

## Extended list of transfer failure reasons

Failed transfers now report more specific failure reasons:

* `number_not_found`
* `number_incomplete`
* `destination_unavailable`
* `rejected_by_destination`
* `transfer_blocked_by_carrier`
* `carrier_unavailable`
* `routing_loop`
* `media_negotiation_failed`
* `transfer_method_unsupported`

Find every state, reason, and SIP code in the [transfer outcome states reference](/transfer-outcome-states).

## September 25, 2026

## Prompt Reuse metric

![Agents Performance card on the prompt reuse tab, showing one agent at 74% and another at 3%](https://storage.googleapis.com/granular-changelog/doc-images/prompt_cache.png)

**Prompt Reuse** is a new metric in [Analytics](/collect-analytics) that shows the health of your agent's prompt. It measures how much of the prompt the AI model reused instead of reading it again.

Use it to understand why some agents respond faster than others: the more of its prompt an agent reuses, the lower its latency in the call.

Learn more about [Prompt Reuse](/collect-analytics#prompt-reuse).

## September 23, 2026

## Run simulations from the agent editor

![Test menu in the agent editor with Simulation selected, next to the Simulations panel listing the agent's test suites](https://storage.googleapis.com/granular-changelog/doc-images/changelog_simulations.png)

You can now create and run [test suites](/simulations) without leaving the agent editor. Change a prompt, rerun the suite, and see what passed or failed right next to the agent.

## September 22, 2026

## Emails

![Post-Call Email action named email\_summary with its list of recipient addresses](https://storage.googleapis.com/granular-changelog/doc-images/post_call_email_1.png)

Your agent can now send an email once the call ends. Attach a [Post-Call Email](/post-call-email) action to any agent and pick who should receive it.

## September 18, 2026

## Synthflow TTS for multilingual agents

![Synthflow TTS selected as the voice model on a Multilingual agent](https://storage.googleapis.com/granular-changelog/doc-images/multilingual_synthflow_tts.png)

Agents set to **Multilingual** can now use [Synthflow TTS](/voice-configuration#synthflow-tts) as their voice model or fallback. One voice covers the whole conversation, including when the caller switches language mid-call.

## Custom action response time

![Response time on a custom action in the Actions tab of call details](https://storage.googleapis.com/granular-changelog/doc-images/custom_action_response_time.png)

[Call details](/logs#call-logs) now shows the response time of every custom action. Open a call, check the **Actions** tab, and find the slow endpoint behind a long silence.

## Call quality metrics on every call

![Call quality section in the Telephony tab of call details](https://storage.googleapis.com/granular-changelog/doc-images/call_quality_telephony.png)

The **Telephony** tab now reports [call quality](/sip-call-ladder#call-quality) for every call, so you can rule out the network without pulling a PCAP. The same measurements are on the [Calls endpoints](/api-reference/platform-api/calls/list-calls).

## September 17, 2026

## Auto-overage for subaccounts

![Auto-overage toggle on a subaccount's Limits & Capabilities tab](https://storage.googleapis.com/granular-changelog/doc-images/autoverage-subaccounts.png)

Parent accounts now control whether a subaccount can call past its included minutes. Turn on [Auto-overage](/limits-and-capabilities#auto-overage) and the extra minutes are billed to your account at your per-minute rate.

## 200 voices for Synthflow TTS

[Synthflow TTS](/voice-configuration#synthflow-tts) now offers 200 voices instead of 12, so you can match a voice to your brand instead of settling for the closest fit. Filter the **Voice** selector by accent, gender, or language, and play a preview before you assign one. Voices already on your agents are unchanged.

## September 16, 2026

## Time to human on warm transfers

Warm transfers that connect now record `human_connected_at`, the moment the caller actually reached a person, not just when the transfer started. See [transfer timestamps](/transfer-outcome-states#transfer-timestamps).

## New transfer outcome states

A transfer that reaches a phone menu, a voicemail greeting, or a busy line now reports that instead of a generic timeout. If you match on outcome state, add the values from the full list of [transfer outcome states](/call-transfers#transfer-outcome-states).

## Action execution timeline in webhooks

A transfer that retried three times used to show up as one attempt in the post-call webhook. The new [action execution timeline](/webhooks#action-execution-timeline) lists every attempt and the number each one dialed.

## September 14, 2026

## Use the new Synthflow app

![The new Synthflow app at app.synthflow.ai](https://storage.googleapis.com/granular-changelog/doc-gifs/appsynthflowai_compressed.gif)

The new Synthflow app runs at `app.synthflow.ai`, with faster page loads and more responsive navigation. Turn it on for your workspace from [Early Access](/early-access).

The [guide](/new-synthflow-app) covers what changes and the current known issues.

## September 7, 2026

## Official ChatGPT plugin

![Synthflow AI integration with ChatGPT](https://storage.googleapis.com/granular-changelog/doc-images/openai_cover.svg)

Synthflow's official **ChatGPT** [plugin](https://chatgpt.com/plugins/plugin_templated_apps_6a8d61e3eb088191a6116aa249be72cd?q=synthflow) is now live. Build and manage voice agents from a conversation in ChatGPT, without leaving the chat.

See the [guide](/openai) to get started.

## September 3, 2026

## Voice Widgets move to the new design

![Upgraded Voice Widget](https://storage.googleapis.com/granular-changelog/doc-images/widget_v3.png)

On **September 16, 2026**, every remaining [Voice Widget](/create-an-agent#voice-agent) moves to the [upgraded design](/changelog/2026/6/30) and faster real-time backend. No action is required: the embed already on your site keeps working.

The [Voice Widget migration guide](/widget-migration-guide) explains what changes and how to test the new embed before then.

## September 1, 2026

## Improvements to speech recognition

![Speech Recognition setting in Additional Settings with the Faster and High Accuracy options](https://storage.googleapis.com/granular-changelog/doc-images/speech_recognition_modes.png)

The [Speech Recognition](/additional-settings#speech-recognition) setting now gives a clearer trade-off between speed and precision. Choose **Faster** for the lowest latency, or **High Accuracy** when the agent needs to capture numbers reliably, such as phone numbers, order IDs, and account references. High Accuracy costs some latency in exchange.

You set it under **Additional Settings** in the [agent editor](/the-agent-editor).

## August 26, 2026

## Current date and time system variable

![All Variables panel in the prompt editor showing agent\_current\_time in the System Variables list](https://storage.googleapis.com/granular-changelog/doc-images/system_variables_current_time.png)

Agents now have access to the current date and time on every call. The new `{agent_current_time}` [system variable](/variables#system-variables) returns it in the agent's [timezone](/general-configuration#timezone) as ISO 8601 with a UTC offset, and works in prompts and [custom actions](/about-custom-actions#variables).

## August 25, 2026

## Non-enterprise plans now run on Synthflow LLM

Accounts that are not on an enterprise plan run on **Synthflow LLM**, our model built for voice agents and tuned for real-time phone conversations, with lower latency and more natural turn-taking than a general-purpose model. Third-party models, including the GPT family, are no longer available on these plans.

Synthflow LLM is the only option in the **AI Model** selector under [General settings](/general-configuration). Existing agents are migrated automatically, so no action is required in the dashboard.

API requests that set `llm` to a GPT value are still accepted and the response looks normal, but the agent stays on Synthflow LLM. Nothing in the response signals that the value was ignored, so update that field in your own automations.

Enterprise accounts are unaffected by this change.

## August 19, 2026

## Filter call logs by phone number

![Phone Number filter open on the Call Logs page with a customer phone number field](https://storage.googleapis.com/granular-changelog/doc-images/logs_phone_number_filter.png)

Call logs can now be filtered by the customer's phone number, so you can find a call when the number is all you have. The filter matches calls to and from that number, and combines with the date, agent, duration, type, and status filters.

## August 18, 2026

## Campaigns

![Campaigns list in the Synthflow portal showing status and progress for each campaign](https://storage.googleapis.com/granular-changelog/doc-images/campaigns_list.png)

Call an entire list with one request. [Campaigns](/batch-calling) dial your recipients over time, as fast as your concurrency allows. Create and control them through the Platform API, pause, resume, or cancel at any point, and watch progress in the portal under **Campaigns**.

Available on our Enterprise plans. Reach out to our support team to activate it on your account.

## Business Hours

![Business Hours panel in the agent editor showing the Limit agent to business hours toggle, the agent local time readout, and the weekly hours for each day](https://storage.googleapis.com/granular-changelog/doc-images/business_hours.png)

Your agents can now keep office hours. Set [business hours](/business-hours) for each day of the week in the agent editor, evaluated in the agent's own timezone, and pick what happens to inbound calls outside them: decline the call, transfer it, or run a custom action. Outbound calls placed while the agent is closed are declined.

## August 17, 2026

## Advanced Synthflow LLM

![Advanced Synthflow LLM option in the agent model selector](https://storage.googleapis.com/granular-changelog/doc-images/synthflow_llm_advanced.png)

Meet our **Advanced Synthflow LLM**, the strongest reasoning model in the Synthflow family. It handles complex logic and long prompts, so agents with deep branching, detailed conditions, and long instructions stay accurate.

Use it when your prompt has outgrown [**Synthflow LLM**](/general-configuration), which stays the default.

## Subaccounts API: Reset minutes used

Subaccount usage counters can now be reset. Set `minutes_used` to `0` on [`PUT /subaccounts/:subaccount_id`](/api-reference/platform-api/subaccounts/update-subaccount) and the customer's cycle starts fresh, so you can run their subscription on your own billing schedule.

## August 14, 2026

## 8x8 Contact Center integration

You can now route inbound 8x8 Contact Center calls to Synthflow AI agents. Import an 8x8 number in Synthflow to receive a generated 12-digit routing identifier, then use it in your 8x8 Forward to External IVR flow. See the [setup guide](/sip-with-8x8-contact-centre) for instructions.

## August 5, 2026

## Phone numbers API: Five9 and RingCX

You can now import [Five9](/sip-with-five9) and [RingCX](/sip-with-ringcx) numbers through the [`POST /custom-numbers`](/api-reference/platform-api/phone-numbers/create-custom-number) endpoint. Synthflow sets their SIP domain automatically.

_Showing the 20 most recent of 96 entries. Append `/llms.txt` to the changelog URL for the complete index._