---
title: ruby-agent-9-21-0
source: https://docs.newrelic.com/docs/release-notes/agent-release-notes/ruby-release-notes/ruby-agent-9-21-0
---

> #### ⚠️ IMPORTANT
>
> We recommend updating to the latest agent version as soon as it's available. If you can't upgrade to the latest version, update your agents to a version no more than 90 days old. Read more about [keeping agents up to date](https://docs.newrelic.com/docs/new-relic-solutions/new-relic-one/install-configure/update-new-relic-agent/).
>
> See the New Relic Ruby agent [EOL policy](https://docs.newrelic.com/docs/apm/agents/ruby-agent/getting-started/ruby-agent-eol-policy/) for information about agent releases and support dates.

## v9.21.0

-   **Feature: In Serverless APM mode, use event source name as transaction name prefix**

    The agent will now use the event source name as a prefix for the transaction name in Serverless APM mode. This will help to better identify the source of the transaction in the New Relic UI. [PR#3245](https://github.com/newrelic/newrelic-ruby-agent/pull/3245)

-   **Bugfix: Revert changed logic for how we track the thread the span starts in**

    This change restores the previous behavior of tracking the thread the span starts in, addressing issues that arose from the updated logic. Thank you [@david-zw-liu](https://github.com/david-zw-liu) for bringing this to our attention. [PR#3248](https://github.com/newrelic/newrelic-ruby-agent/pull/3248)