Microsoft has decided to push the final deprecation of client access rules to September 2024. However, only rules that can’t be migrated can be used until then. All other client access rules will stop working in September 2023. Microsoft isn’t clear about what technical limitations might allow rules to work for the extra year, nor do they say how tenants can check except by “opening a support ticket.” Although it’s good to move to conditional access policies, Microsoft really could communicate better.
https://office365itpros.com/2023/04/14/client-access-rules-2023/
