Based on the suggestions from @MrSharky, we’ve added the ability to mark an artwork as seen on a past date:
If you want to see your past record of seens and hunts, there is a new ‘Logbook’ page (under the user menu at the top right):
In the future, this will be integrated with the ‘Exploration’ page that @Noa_Heutz added to the app, for a unified overview of your spotting progress.
Received the email about this earlier today - fantastic! Went to take a look but I can’t find it on either the (Android) app or on my iPad.
I can see the logbook feature, which is really handy, but can’t find where to be able to actually log an item as being seen in the past… perhaps it’s just me being a bit thick! 
Do you have any other instructions/advice on how to find/use the feature, please?
Fair point - I did not explain this very much. This feature is only available on the website at the moment. There, when you click the ‘seen’ button, it will show you a little drop-down menu with this being one of the options.
I’ve hidden it a bit for now, since I don’t want to overwhelm people with options until they might need them.
It’s also something I built quite quickly on a Friday night, so let me know what you think!
Aah, thank you for the extra detail. I’d clicked an artwork as seen, but in the app; not on the website; so didn’t get the extra option… however, I’ve now done it on the website and can see the date picker (yay!) but it’s locked for me, sadly. 
I’m so looking forward to being able to use it though, so thank you for adding the feature. 
EDIT : The datepicker works when I access the site via the browser on my phone (using Chrome) but not on the iPad (Safari). The joy of browser differences when coding! 
As a slight aside… does it store the “seen (in the past)” data in a different way to the normal “seen” data (I can’t imagine why it would though) as I have logged a few of my sightings in cities I’ve visited over the past few years, but they are not showing in my leaderboard numbers… or are these calculated on a per-city basis?
It’s not a big issue, I’m just interested in how it works from a coding point of view. 
Oh, I’ll have a look at that Safari on iPad issue, that’s strange!
On how they’re stored - they’re indeed just the same as normal ‘seens’, but with a different timestamp. It shouldn’t affect leaderboards, but honestly the current versions of both of the leaderboards we have on the platform aren’t very consistent. I’m hoping to get some time to build a better unified version of this sometime relatively soon!
Tried yesterday to enter a date, I couldn’t select a date (and probably a kind of calendar should appear?)
Interesting, must be something weird with certain browsers. Which one were you using?
This is what it is supposed to look like when you tap/click on it:
I’ve also just made a change to use the same date selector we use on the dashboard - can you give it a try and see if it makes it any better?
