There's a removal notice here for WebSphere Liberty, which is built from Open Liberty so the same applies: https://www.ibm.com/docs/en/was-liberty/nd?topic=liberty-removal-notices#rwlp_remfeat__29001_se8

With a more detailed explanation here: https://community.ibm.com/community/user/blogs/macdara-butler/2025/11/13/liberty-java-8-support which says:

The final Java 8 release of Liberty has been changed to 28.0.0.12, with iFixes provided until December 2030.

29.0.0.1 will be the first release of Liberty to not support Java SE 8, as noted in the Liberty Removal Notices.