I’m trying to save my files and it keeps saying unable to save, save as an older version. I then don’t have the option to save as an older version in the popup save window, and I am also unable to upload to Trimble Connect as a backup. Is there a plan to fix this? Seems like a very shoddy design flaw, and is inconsistent. I keep losing my work because of this flaw, and tempted to shift across to another software should it continue.
Why would something like this pass testing? 
The decision to remove the ability to save as an earlier version was deliberate.
I assume it’s to ‘encourage’ you to up grade to the latest version, although recent versions of SketchUp make a new version SKP format that is backwardly compatible.
There is a Ruby based extension by Dezmo that allows backwardly compatibility saving of your newest SKPs…
https://forums.sketchup.com/t/save-to-previous-version/274248/2
I’m not seeing the problems you encounter.
Edit: There have been others with the same problem. This extension could be a solution for you:
Select All, Copy, New, Paste in Place. Save As.
Quit SketchUp, Open SketchUp, open the problem file…
If you are missing work / geometry use the copy / paste file you just made to replace what you need.
It is not the easiest help, but at least you won’t lose anything.