How do I save "DateTime imported" value in Digikam?

[Remco Viëtor]

On vendredi 19 mai 2017 08:37:14 CEST Gilles Caulier wrote:
> no DK do not touch unknown or un-managed tags.
> 
> But don't forget Exiv2 is used at end in background. Something
> unwanted can be done in this area, but as i know nothing is removed
> intentionally by Exiv2 at metadata rewriting stage.
> 
> Gilles Caulier
> 
> 2017-05-19 8:29 GMT+02:00 Mica Semrick <mica at silentumbrella.com>:
> > I would consider it very bad behavior to remove or ovverwritw ever element
> > in the XMP file. I certainly hope digikam does not have this behavior.
> > 
> > -m
> > 
> > On May 18, 2017 11:16:56 PM PDT, "jdd at dodin.org" <jdd at dodin.org> wrote:
> >> Le 19/05/2017 à 07:48, Remco Viëtor a écrit :
> >>>  about. But such unknown tags may get lost on rewriting the file.
> >> 
> >> really? this is pretty odd.
> >> 
> >> some tag may be replaced though (editor's name, for example)
> >> 
> >> jdd

Good to know (I suspected as much as Darktable's tags survive intact), but 
afaik, XML doesn't /require/ a program to preserve unknown tags.