Thought about updating createdon date in Dynamics 365

Short Answer:

You cannot directly update the CreatedOn date of existing records in Microsoft Dynamics 365 once they are in the system. The CreatedOn field is a system-managed attribute and is considered read-only after the record is created. The only supported way to set a custom CreatedOn date is during the initial data import by using the "Override Created on" feature. Once records exist, their CreatedOn date cannot be changed through supported methods.

Detailed Explanation:
Microsoft Dynamics 365 treats system fields like CreatedOn as immutable after the record is created. This is by design to maintain data integrity and auditability. Once a record is saved, its CreatedOn date is considered a historical fact—representing the exact date and time that the record entered the system—and cannot be altered directly through the user interface, the SDK, or workflows.

Supported Method: "Override Created on" During Import
If you need certain records to have a specific CreatedOn date (for example, when migrating data from another system), you must do this at the time of data import. Dynamics 365 allows you to override the CreatedOn date during the initial import process by using a CSV or XML file that includes a column mapped to the CreatedOn field, and by enabling the appropriate setting during import.

1. Prepare Your Source Data:
   Include a column (e.g., "Created On") in your source file and fill it with the desired date/time values.

2. Import Wizard Settings:
   When using the Dynamics 365 Data Import Wizard, select the option "Allow importing record created dates from source system". This instructs Dynamics 365 to read the provided CreatedOn values and use them as the record’s actual created date/time upon creation.

3. Perform the Import:
   Complete the data import. Newly created records will now have the specified CreatedOn date.

After the Records are Created:
If the records have already been created without using the override feature, there is no supported mechanism to change the CreatedOn field. Attempting to do so through unsupported means (e.g., direct SQL updates or unsupported tools) could lead to system instability, data corruption, or issues with future updates and support from Microsoft.

Reference Article:
For official guidance from Microsoft, please see the documentation on importing data and overriding the CreatedOn date:
Import accounts, leads, or other records - Override Created On

This article explicitly states that the CreatedOn date can be set only at the time of import and provides step-by-step instructions for doing so. Once the records are imported, the CreatedOn date cannot be modified using supported methods.