@ Letot Jean-Jacques
RE: Totally agree to do the test.
Great, please create a temp admin account using this plugin:
Reply back, as a private reply, with the login link. If it gets rejected as spam, try the comment form at the very bottom of the page. If rejected, please let me know so I can whitelist your IP/email. Do not keep trying to post it over and over, the anti spam bots will flagg you and reject all further posting until I whitelist you.
RE: Will the change to YYYY / MM / DD be permanent with future updates?
Yes, if testing is successful, this change will be made permanent. I expect the test to correct the issue. This change will only affect when adding or editing an entry. The display date format will still respect what you have in the settings.