Error to export XML Crossref DOI - after update OJS 2.4.8

After performing the update OJS 2.4.8 we are not able to run the export plugin Crossref in XML, with the error message:

“Fatal error: Using $this when not in object context in /home/seer/ojs-2.3.5/plugins/importexport/crossref/ : runtime-created function on line 1”.

I ask, any tips to solve this problem?


What version of PHP are you running?

What does your line 217 of plugins/importexport/crossref/ read?