Q. Will the Taylor & Francis IPv6 cutover in January 2023 affect my hosted EZproxy access to their content?
A. No. The IPv6 cutover applies only to dual stack systems.
Q. What is a dual stack system?
A. A dual stack system supports both IPv4 and IPv6 addresses.
Q. Is OCLC a dual stack system?
A. OCLC owns the entire IPv4 range 132.174.*.* and is not a dual stack system so access will not be impacted.
Here is the unmodified, official announcement from the Taylor & Francis website as of March 2022 (including typos) https://help.taylorfrancis.com/librarians_institutions/s/article/Does-Taylor-Francis-eBooks-support-IPv6-addresses
“Does Taylor & Francis eBooks support IPv6 addresses?
We are updating Taylor & Francis eBooks to support IPv6 traffic to the website, and will start to make this switch from 15th January 2023.
Most newer computer and mobile devices support both IPv4 and IPv6, which is referred to as a dual stack system. Currently Taylor & Francis eBooks only supports the IPv4 addresses presented by dual stack systems, but we will switch to supporting only IPv6 addresses from 15th January 2023. Once we switch over to support IPv6 traffic, we will require your IPv6 ranges to authenticate your users and provide access to the content purchased by your institution. After switch over, we will not be able to use IPv4 ranges for any dual stack machines.
For all dual stack devices, you should update the IP Ranges page in your Institutional Settings with your IPv6 address ranges. Please do not remove your IPV4 address ranges as we will continue to use them to authenticate your access until we switch over to IPv6. Please ensure you have updated your IPv6 address ranges using our self-service feature before 15th January 2023 to ensure your users continue to be properly authenticated.
Any older computers or devices using only IPv4 addresses do not require your IP ranges to be updated, and will continue to be supported after switch over.”
As you can see from above, IPv4 networks will be supported and continue to authenticate after the cutover.