We upgrade stuff all the time, we're replacing the floors and counters in September (along with the A/C, which isn't something I'm going to put in a photo anyway). I have no intention of doing anything other than posting final photos on our Facebook page and eventually getting the photographer back out there to take updated pictures.
Since your upgrades are more extensive, I'd let guests know right before check-in where to go to find photos of the final remodeling outcome.
Love that coffered ceiling!
I change the furnishings in my cabin and chalet with some frequency. I have a note in my advertising and in my contract stating that linens and furnishings may change without notice.
With regard to the major update and renovation that you are doing, as long as you are not changing something like removing a TV and not replacing it, just let your 2019 guests know that you are "delighted to have them visiting your newly renovated home", and invite them to comment on how they like the new furnishings. I think that most guests would want to know that you take care of your home, and will appreciate a new renovation versus a tired home. Congrats!.
Gorgeous! And so exciting!
I can't imagine guests having a problem with a free "upgrade" to your newly renovated home.
When you email, though, I would try to be as positive and at the same time nonchalant about the changes as possible. Something with a subject like "Guess what we've been up to at blahblahpropertyname?" Then in the message itself, I'd be photo-generous and word-stingy. You could even set up a temporary (free) website with a hoster like weebly or wix so you could give the full mostly photo) details of the reno so guests share your excitement about the changes.
One lesson learned .... Be 100% certain that everything works as planned and that clean up has been really thorough. We did a tiny upgrade once (new bunkbeds) and my crew missed cleaning some debris (a few screws and a drill bit. Luckily, we stayed next and found the items before guests did. Staying in your place after any upgrades before guests do is a great idea, and was a happy accident in my case. I didn't have the sense to plan it that way in advance but was glad I did after the fact.
Hope that helps.
I think the guests will be very happy. They will see it as an upgrade. I had replace a sofa and love seat with a really nice section 3/4 of the way through my season last year. Many guests that booked based upon prior pictures were very complimentary of the new sectional. I also state in my listing that the pictures are up to date as of Month, Year.
we just finished a 2 year long new custom VR construction.. not even a remodel - we remodel a bit all the time. I posted the progress photos on FB and Instagram, sent newsletters.. etc. My personal observation is that 99.5% of people do not care about "work in progress", they only mildly interested to see the final product. It may be interesting and exiting to your the owner to see the transformation (I know, I lived it for 2 years!) but not to the guests. FWIW.