INTL_IDNA_VARIANT_2003 is deprecated

I found out that the last parameter is just the path for the output. I modified this but it it still mot working. So I am going through the log to clean up all the errors. I am seeing this one. Anyone know what this is and how to get rid of it?

Severity: 8192 --> idn_to_ascii(): INTL_IDNA_VARIANT_2003 is deprecated /app/system/libraries/Form_validation.php 1234

I am using CI3

proof that an old dog can learn new tricks