Ending support for TLS 1.0 and 1.1
Upgrade by March 4, 2020
TL;DR
On March 4, 2020, Slack will end support for Transport Layer Security (TLS) versions 1.0 and 1.1. In advance of this, we will implement a 24-hour test deprecation on February 19, 2020.
If your Slack app or organization is using an unsupported version of TLS, requests sent to any Slack service will fail. We are making this change to align with industry best practices for security and data integrity.
What is TLS?
TLS enables a secure connection between two web-based applications that share information — like your IT systems and Slack. This is the most widely deployed security protocol and is common for most modern applications, including web apps like Salesforce.
There are multiple versions of TLS, including 1.0, 1.1, 1.2, and 1.3. You should discontinue use of versions 1.0 and 1.1.
Next steps for admins
Ensure your organization can continue using Slack without interruption. Verify your team is using the latest version of Slack on desktop and mobile, or in a supported browser version.
To view a list of affected users and applications in your workspace, follow the instructions documented in our Help Center article, Transport Layer Security (TLS) in Slack.
Next steps for developers
Confirm all app(s) you’ve built for Slack are using TLS versions 1.2 or higher. Requests sent to any Slack endpoint will fail. This includes apps using the Slack API, incoming webhooks, and custom integrations.
View your affected Slack app(s) here, and upgrade any that are not already using TLS 1.2 or higher. This may be a matter of updating your code with a newer version of Python, PHP, or other languages.
If your app is built with modern programming languages, HTTP libraries, and frameworks, changes are unlikely. Also, if your organization uses 3rd-party Slack apps, confirm installation of the latest versions.
Need more answers? Contact our support team through feedback@slack.com.
