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OCLC Support

TLS security enhancements

Important information related to OCLC’s TLS security enhancements.

What you need to know about OCLC’s TLS security enhancements

To continue providing best-in-class security and to align with evolving industry standards, OCLC will discontinue support for Transport Layer Security (TLS) versions 1.0 and 1.1.  

OCLC® systems accessed through the internet use the TLS encryption protocol for data protection. Internet browsers used to access OCLC systems need to use TLS version 1.2 or higher. Current versions of most browsers such as Chrome, Internet Explorer, Edge, Firefox, and Safari require TLS 1.2 or higher. Therefore, most members will not be impacted and can continue to access OCLC systems as they do today.

For additional questions, please contact OCLC Support in your region.

Why OCLC is making this change

OCLC will make this change because TLS versions 1.0 and 1.1 are older encryption protocols that the industry and the Internet Engineering Task Force are actively moving away from. Major browser companies, including Apple, Google, Microsoft, and Mozilla have announced that they will no longer accept TLS versions 1.0 and 1.1. 

Impact of change on your access to OCLC systems

Any member accessing an OCLC system from a browser using TLS 1.0 or 1.1 will need to upgrade to a modern browser that uses TLS 1.2 or higher.

Upgrading your browser

You can learn more about upgrading your browser by using the links below, or you can contact the IT support team at your organization for help. 


OCLC API users will need to confirm that their client application(s) supports TLS 1.2 or higher. Please consult with the owner of your client application(s) to confirm how this should be done, as systems vary widely. Below are some examples of how you can check for a success message using three common programming languages.




import urllib.request

result = urllib.request.urlopen('')


require 'net/http'

response = Net::HTTP.get ('', '/index.html')


STunnel connection

If you have trouble accessing OCLC systems, contact your organization’s IT support for assistance with upgrading STunnel to use TLS 1.2 or higher.