my $xsltcache = C4::Context->preference('XSLTCache') // 1;

    unless ($xsltcache) {

        # Do not use cache

        $xslth->refresh();

    }

$DBversion = 'XXX';  # will be replaced by the RM

if( CheckVersion( $DBversion ) ) {

    $dbh->do(q{

        INSERT IGNORE INTO systempreferences (variable,value,options,explanation,type)

        VALUES ('XSLTCache','1',NULL,'Enable/disable XSLT cache','YesNo')

    });

    SetVersion( $DBversion );

    print "Upgrade to $DBversion done (Bug 2xxxx - Add XSLTCache system preference)\n";

}

        -

            - "XSLT cache: "

            - pref: XSLTCache

              choices:

                  yes: "Enabled"

                  no: "Disabled"

            - Disable for XSLT files edition and enable for better performance.