I was using LR4 and purchased the LR6 desktop version. I upgraded my catalog (copied, renamed, etc.) but I was having issues in LR6 bc it is not working properly with psd and tiff files (there's discussions on this in other places). So I went back to LR4, using my old LR catalog since I hadn't done much but play around in LR6 and wasn't worried about keeping those changes. I'd like to start using LR6 instead again and just not do any psd or tiff work in LR. What's the best way to get my current LR4 catalog (since I have been using that one and have made changes to it) to be the one I use in LR6 (deleting or overwriting my original LR6 'upgraded' catalog)? And it seems like you pretty much have to just decide which version to use and stick with it right, since the changes are made in the program and not to the actual files themselves? Thanks in advance for the help.
You can either delete the previously created Lr6 catalog or Zip it up deleting. Next time you launch Lr6 it will ask to update the latest version of your Lr4 catalog
Lightroom 6 can only utilize your LR 4 catalog if it upgrades it to the database format that conforms to Lightroom 6. So I'm not really sure what you are expecting to be able to do.