[Koha] Perl module ReadOnly::XS

Dear all, I recently upgraded to 3.16 and when I look at the Perl Modules page in About Koha I see that ReadOnly::XS is showing in red as not installed. I am running Ubuntu 3.5.0-49.generic and when I type sudo cpan install /ReadOnly::XS/ It returns Readonly::XS is up to date (1.05). But it still displays as red and not installed under Perl Modules in About Koha. Does anyone have any ideas on where I'm going wrong? Matthew Charlesworth