Syntax error unexpected ? at various pages

[River_rush]

I am trying to upgrade pixarcarsdiecast.com from 5.4.1 to latest and get the above message, completely breaking the forum, any ideas please :o

[Dave]

Can you show us the entire error message? Good chance you are running a PHP version that is not compatible with the vBulletin version you are trying to upgrade it to.

[River_rush]

Can you show us the entire error message? Good chance you are running a PHP version that is not compatible with the vBulletin version you are trying to upgrade it to.
Such as Parse error: syntax error, unexpected '?' in /home/******/public_html/forum/core/vb/request.php on line 68
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[BulliM]

Simply do update again. Are ALL folders and files updated? Delete all old files and then upload all new files. Look at both config files. Are that one in root directory renamed to config.php? Is .htaccess into it? After that, do your update, should be successful.