What is the date of appointment letter to be mentioned for an employee who had joined earlier, but not given any proof of employment ?

Dear All, Good Morning.
I would request for your valuable suggestions for the following query. Our organizations is having 2 wings of employees as Project team and on-rolls. Due to the change in our management, currently we are moving few of the existing project team employees to on-rolls. For some reasons, they are under project team but working in on-roll responsibilities. They all joined in August 2022. Now we need to issue an appointment letter from the DOJ. In such case, shall we mention the current date as the date of issuance and their date of joining as Aug 2022. If so, shall we mention with a clause of considering and recognizing their service period with DOJ. Thank you for your assistance.

Hi,
Letter date can be current date or date of issue. But DOJ should actual date of joining so as to ensure service continuity and also to claim future separation benefits.