No one knows which version of Office you had then, and which you have now.
The current version of Office is called Microsoft 365. It gets updated on a regular basis and once it has been updated, you can't go back to the way it was before. That's by design - the idea is that all users have the most up-to-date version of the software.
There are a few earlier versions of Office that are still supported, depending on whether you are using Windows or MacOS. For example, if you use Windows, Microsoft Office 2024 is still supported. You can't 'downgrade' from Microsoft 365 to Office 2024. Instead you have to uninstall Microsoft 365 and replace it with Office 2024.
If you tell us which version of Office you had then, and which you have now, and what operating system you use (e.g., Windows 11, Windows 10, MacOS Tahoe 26) we can tell you what your choices are. But you need to know ... nothing from 20 years ago is supported today.