Peter Dyballa <Peter_Dyballa@Web.DE> writes:

> I think it's close to impossible to reproduce the bug when launching GNU Emacs with -Q, because dates in diary file are read and they must be interpreted the proper way, the European and natural way, as day - month - year (or in reverse):
>
> %%(diary-anniversary  4  6 1862) Geburt von Karl Valentin in München-Au als Valentin Ludwig Fey %d Jahren
> %%(diary-anniversary  4  6 2020) Tod von Rupert Neville Hine
>
> Today all my versions of GNU Emacs 28.x report that it's the birth date of Karl Valentin and the death date of Rupert Hine:
>
> 	Sunrise 06 Uhr 53, sunset 20 Uhr 04 at Friedberg (13:11 hrs daylight)
> 	Geburt von Karl Valentin in München-Au als Valentin Ludwig Fey 160 Jahren
> 	Tod von Rupert Neville Hine
>
> The versions 27.x display that today's date (probably) was not much meaningful for the two men.

I'm not sure I understand what you mean here, but perhaps I'm not
reproducing the problem correctly.

If I put the following inn ~/.emacs.d/diary, and then start Emacs 27.1
with -Q, and then say `M-x diary':

%%(diary-anniversary  4  7 1862) Geburt von Karl Valentin in München-Au als Valentin Ludwig Fey %d Jahren
%%(diary-anniversary  4  7 2020) Tod von Rupert Neville Hine

I get