@User_T1TK5 From the below documentation, Under table

24.R1 ,row Planned for deprecation , Following was mentioned

The Receivables Aging by Accounting Date preview feature, available since release 22.R3, will become the default AR Aging feature in release 24.R2. 

https://docs.oracle.com/en/cloud/saas/analytics/26r1/fawwn/index.html#GUID-27505232-5CDD-41B3-9ED2-C253139B49CA

Since this feature is made default from release 24.R2 and it is not showing under 26.R1 preview features list.

During my research ,Found below KB article where few functional points were mentioned

KB83255 FAW: Enabling Feature "Receivables Aging By Accounting Date" Makes No Change In "Financial - AR Aging" Subject Area

• Receivables aging creates snapshots based on the accounting date of the transactions.
• It does not use the Invoice date or Application dates to decide the snapshot which was the case with the old aging.
• All transactions, activities, unapplied receipt activities are based on the accounting date.
• Aging metrics continue to use Invoice date or Due Date based on the metrics that you select.
• Aging is not based on the Accounting date but the snapshot activities are decided based on the accounting date.

https://docs.oracle.com/en/cloud/saas/analytics/23r2/faiae/chapter-introduction.html#GUID-27823FCE-A100-4D48-BBEF-B496C152B414

Receivables Aging by Accounting Date :

This feature provides the option to build AR aging periodic snapshots based on accounting date instead of transaction or activity date in the existing AR Aging subject area.

kindly please check if above points are helpful.