Some of my customers are transitioning from 32-bit versions of Crystal Reports to Crystal Reports 2020, which is 64-bit. This creates some issues since ODBC/OLEDB drivers are either 32-bit or 64-bit. Switching to CR 2020 requires different drivers and (if using ODBC) different ODBC Data Source Name (DSN) entries.
The same applies to UFL function DLL files. For instance the free ufl named u2lwin32.dll only comes in a 32-bit version. Some commercial ones come in both 32-bit and 64-bit editions. Switching to CR 2020 requires that you use 64-bit UFL libraries.
The good news is that RPT files in CR 2020 are backward compatible with earlier versions, probably back to Crystal Reports v9. So you can modify and run a single RPT file in both CR2020 and earlier versions. But you do need different connectivity. What my customers are doing is naming the connections the same in both the 32 and 64 bit environment. That way users in both environments can run the same report without modification.
If you run into any strange behaviors in using CR 2020 or in the transition, please let me know and I will share with others.