For a long time, the latest version was not installed on my PC. Because of this, something happened, and now the program began to appear a lot of errors when editing files. This made me update the software. This helped me a little, but important files now don't open in the updated version. I tried to use additional plug-ins for this, but they do not work completely. What else can I try?

Try opening the .dbf file in Excel or other program that supports opening the .dbf format.
Once opened in Excel you should be able to view the file, delete any "bad data", and resave to a new name (with the .dbf extension).
Also possible to create a new table with the structure of the old table, append records from the old to the new. May salvage records until the corruption is encountered.
But there is a situations which requires dbf recovery online by various ways
https://support.microsoft.com/en-us/help/193952/how-to-troubleshoot-to-resolve-suspected-corruption-in-visual-foxpro
https://dbf.recoverytoolbox.com/online/

Hi,

Usually what happens DBF file is corrupted due to n no. of reasons like malware attack, virus attack, hardware failure etc. It is a human tendency to not able to avoid such situation due to several reasons. Because of which .dbf file gets corrupted, as it is prone to error.

Simple way to fix it is user should use some of the recovery softwares which I come across:
http://www.databasefilerecovery.com/dbf-recovery.html

For more clarifications: http://www.databasefilerecovery.com/blog/dbf-file-recovery.html