Hello,
The error message isn't instructing you to change the year of the namespace for the schemaRef element to 2003. Instead, it's indicating that it's the wrong namespace and that you should use the linkbase namespace instead, which coincidentally is from 2003. There isn't a 2003 version of the inlineXBRL namespace; the available versions are 2008 for the 1.0 specification and 2013 for the 1.1 specification, neither of which are used to define the schemaRef element.
Best regards,
Austin Matherne