Critical Error in Admin

Fatal error::  Uncaught Error: Undefined constant "tru" in /home/[redacted]/public_html/wp-content/plugins/duplicate-post-page-menu-custom-post-type/duplicate-post-page-menu-cpt.php:144
Stack trace:
#0 /home/[redacted]/public_html/wp-includes/class-wp-hook.php(324): Duplicate_PPMC_Init->duplicate_ppmc_admin_notice('')
#1 /home/[redacted]/public_html/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters(NULL, Array)
#2 /home/[redacted]/public_html/wp-includes/plugin.php(517): WP_Hook->do_action(Array)
#3 /home/[redacted]/public_html/wp-admin/admin-header.php(303): do_action('admin_notices')
#4 /home/[redacted]/public_html/wp-admin/admin.php(239): require_once('/home/[redacted]/pu...')
#5 /home/[redacted]/public_html/wp-admin/edit.php(10): require_once('/home/[redacted]/pu...')
#6 {main}
  thrown in /home/[redacted]/public_html/wp-content/plugins/duplicate-post-page-menu-custom-post-type/duplicate-post-page-menu-cpt.php on line 144

Looking at the line specified in the file:

if ( tru !== $support && $diff_days >= 2 ) {

It seems like it should be true, not tru.