Dealing with Emojis that are too new for a macOS version

My app can make PDFs out of emails where the name of the PDF mainly is the subject of the email. How do I deal with emojis which are available on a newer version of macOS and are not available on an older version of macOS?

For instance, the winking eye is available on Sequoia:

But it’s not available on Big Sur:

Is there a better idea than trying to create the file and removing the emojis after an error?

Well, you could do search and replace to look for emojis and keep a list of which are not available.

Or you simply tell clients to upgrade their operation systems. Maybe just an entry in a FAQ.