Need Advice: OpenOffice no longer works

[banjobll]

Open Office 4.1.6, Mac 10.14.6 I have been using Open Office (text and spreadsheet documents) for about 6 years, very happy, no issues. Got new Mac about a year ago and all worked ok initially but now after installing updates, most spreadsheets are inoperable, I can still open and read existing ones but cannot select any portion, cannot modify, copy or paste. I can create new spreadsheets and they are operable but only a very few of my old ones are operable.
1. Is there a compatibility problem with the new Mac OS?
2. Is there any fix?
3. there is a spreadsheet app on the new Mac called "Nunbers" but I am not able to select a[the Open Office spreadsheets into it. Is there a way to do this?

thanks

[Villeroy]

Switch to https://libreoffice.org/ which is the actively developed successor to OpenOffice. OpenOffice has almost died. This forum is the most vivid part of OpenOffice.

[John_Ha]

I can still open and read existing ones but cannot select any portion, cannot modify, copy or paste. I can create new spreadsheets and they are operable but only a very few of my old ones are operable.

The old files have been set to Read Only probably because they come from the old PC. Either change them to not Read Only or click the Edit icon and save them.