Slideshows on Photoshop Elements 2021

1. Using a saved search to bring up the photos, with "oldest first" as the date order, this photo order was not retained in the folder to which the photos were expoerted. The order seems to be by file name in alphabetic order. Any thoughts?

What method did you use to Export the files?  See my recent post here.  It may answer your qustion.

2. The caption doesn't go across with the photo. Is there any way of making that happen?

You can try saving the metadata to the file by using the Ctrl+W command.  But this does not necessarily mean that your photo frame will read the caption in the metadata.  There is no standardized method for the treatment of captions.

OK.  I have just  conducted a test for importing to a backwards version.  In Elements 2021, I gave a star rating, created a caption, and applied a keyword tag and a People tag to two jpg files.  I then saved the metada (Ctrl+W) to one of the files.

I opened Elements 12, which is the oldest version I have on my machine right now, and imported the entire folder containing both files.  During the import, I accepted the opportunity to import all keywords.

The result was that one of the files displayed the star rating, the caption, and the keyword tag.  It also converted the People tag to a regular keyword tag.  The other file (for which I did not save the metadata) displayed none of this information.

Next, I returned to Elements 2021 and saved the metadata to the second file.  After relaunching Elements 12, none of the information was viewable in the grid, but the caption could be viewed in the Info panel under the IPTC tab.

In Windows File Explorer, the star rating and captions are available in the file properties.

So, my suggestion is that you:

•  First import the files into your Elements 2021 catalog,
•   Apply your star ratings, captions, keyword tags and People tags
• Save the metadata to files,
• Import the files to your older version (Elements 10)
• Accept the import of all keywords

You should then be able to create your slideshows in Elements 10 using the search criteria of keyword tags (including People tags converted to keyword tags), star ratings and captions.

Catalogs are not backwards compatible. So you cannot restore a 2021 catalog to an Elements 10 Organizer.  It would have to be the other way around.  Perhaps the best way to keep both catalogs "in synch" would be to use Watched Folders to import all new files into each catalog.  Of course, this does not synch new tags or Albums.  If you tell us a little more about your slideshow workflow, we might be able to suggest other strategies.

Many users retain their older version of the program on their machines for the specific purpose of using the older slideshow feature.  Both versions of the program can be installed without any problems.

You can't compare the old and the new version for slideshow, they are fundamentally different and for different kinds of users.

The old slideshows may be good for your own home use, but today, new users want to be able to share hi-res videos in the mp4 format.

On the other hand, the new marketing orientation of Elements is to integrate the use of automatic AI driven solutions to make things easier for beginners. Rewriting totally the old (32-bits) obsolete technology did not make sense, especially since Adobe prefers to move creative video users towards Premiere Elements, which has all the tools to create advanced videos.