am 13735a2: Merge branch \'readonly-p4-donut\' into donut

Merge commit '13735a255dedd2c2e3b0cff66f0be2e17671f553'

* commit '13735a255dedd2c2e3b0cff66f0be2e17671f553':
  AI 147976: Compatibility mode support. Part 2.