Oracle released update to the AD/TXK on 7th Aug, 2020. The previous version for R12.AD.C.Delta.11 was one of the major updates and there has not been a update to AD/TXK since a long time.
Oracle now released for R12.AD.C.Delta.12 and R12.TXK.C.Delta.12. There are no enhancements for any of the AD utilities and mostly its the bug fixes.
Check the documents below for more details:
Oracle E-Business Suite Applications DBA and Technology Stack Release Notes for R12.AD.C.Delta.12 and R12.TXK.C.Delta.12 (Doc ID 2649885.1)
Applying the Latest AD and TXK Release Update Packs to Oracle E-Business Suite Release 12.2 (Doc ID 1617461.1)