The ship was never in service under the old number, and it will not appear in future official databases (class, registry, Seaweb, Equasis, ITU etc). Leaving yachts aside the IMO number should not be any different after a change of use, provided the engine-room section of the ship is not completely new. (Of course there are a very small number of similar errors)

We will lose the on-site link for the ship if we keep the cancelled number for just six photos.

Thanks for the explaining of the change in IMO number.

But I think we shoot keep the old IMO number as when ship are converted from shipstype. The ships are added into the category of the one the picture was taken

It can happen when an applicant provides credible, though incomplete, data when applying for a number and the connection is not realised at the time. If the new number has been widely used on regulatory certification (flag, class etc) by the time the full story comes to light, then the earlier one is cancelled, though the history does get attached to the new one. So IMO 9805568 is now shown as launched 10/11/2008, with the Chinese yard details (I've changed the number used on SS accordingly)

Another IHS error where they've not made thorough enough checks?

Yesterday I had her out for seatrials.

Rare thing is that they changed her IMO number into: 9805568.
First time I see they changed an IMO number on a ship (execpt for ships converted into a yacht)