Lost filters when upgrading catalog in Lightroom Classic

[49kingdom]

I received a message when opening Lightroom Classic indicating I needed to upgrade my catalog.  When I did the upgrade and got through the slow process I found that my filters (flags) are missing and I cannot figure out how to get them back without starting over.  I still have them in my old catalog but don't know how to get them to the new catalog.  Is anyone familiar with this problem or know how to correct the problem?  Thanks for any help.

John49

[dj_paige]

I found that my filters (flags) ...

I have never heard flags called filters or vice versa. In fact, these two words refer to different things in the Lightroom Classic catalog. So, do you mean the Flag (in this case) that appears at the top left of a thumbnail box, which I have highlighted in green?

[49kingdom]

yes that is what I am refering to, the flags in upper left corner.  They were not carried into the upgraded catalog.

[dj_paige]

Exactly how did you upgrade the catalog? Can you describe the exact step-by-step procedure?