Smartsheet API Deprecating TLS 1.0 Support

Published on 31 January 2019

Smartsheet uses Transport Layer Security (TLS) to provide privacy and data integrity for its API users. TLS is the most widely deployed security protocol on the Internet. As the industry continues to deprecate older, riskier software, Smartsheet is moving to protect our customers use of our software. Consequently, on March 31, 2019 support for TLS 1.0 will be disabled. This change in TLS versioning support should not affect many applications working with the Smartsheet API. However, if TLS 1.0 or 1.1 were explicitly chosen in your code, then your applications need to be changed to use a newer version of TLS. TLS 1.1 will continue to work after March 31st, but like others in the industry Smartsheet will discontinue TLS 1.1 support at the end of 2019. If changes to your application are necessary now, Smartsheet recommends targeting TLS 1.2 or above so additional changes are not needed later this year.

TLS 1.0 was defined in January 1999 as an improvement to the SSL Version 3.0 specification. The authors described the new specification as not dramatically different from SSL, but different enough to not be interoperable. TLS 1.0 has had some vulnerabilities discovered over the last few years and newer versions of TLS incorporate many new defenses to protect users of our software.

To test whether this change in TLS will affect your applications a new Smartsheet API endpoint has been created to simulate a connection that doesn't support TLS 1.0/1.1. To test your applications call, instead of the regular This tls12 endpoint will route your request to the same API servers, but it will block TLS 1.0/1.1 connections at the firewall.

Users of the Python SDK should make sure to upgrade to at least version 1.3. More details can be found on the Python SDK project page. Like, users of the C# SDK should also make sure that their project is using the most recent update.

If you have any questions please leave them in the comments below. Or, if you have issues please reach out to the Smartsheet support team.