All files uploaded, however the upgrader throws this error instantly when I load it:

"Parse error: syntax error, unexpected T_OBJECT_OPERATOR in /home/redacted/public_html/kiextreme.com/forums/system/Member/Member.php on line 3085"

The error_log file is a constant chain of these two:

"[03-Apr-2018 03:25:36 UTC] PHP Parse error:  syntax error, unexpected T_OBJECT_OPERATOR in /home/donaldfl/public_html/kiextreme.com/forums/system/Session/Front.php on line 162
[03-Apr-2018 03:25:36 UTC] PHP Fatal error:  Class 'IPS\Session\Front' not found in /home/donaldfl/public_html/kiextreme.com/forums/system/Dispatcher/Standard.php on line 304"

All files were uploaded with WS_FTP in Auto transfer mode

Okay, the server requirements checker answered my question... Looks like I need to have my host upgrade PHP.

As a general rule, if you see a "PHP Parse error" error pointing to a regular core file, either your PHP version is out of date or you need to reupload the file because it did not upload fully or correctly.

If you see this error on a file that is written by the software (e.g. on a cached theme template file), you likely hit a race condition and the error will be gone when you refresh.