How to update SugarCRM from 6.5.24 to 6.5.26 with SuiteCRM installed?

Hi there,
I tried to update the Sugar security fixes to 6.5.26 on a system with a SuiteCRM 7.8.x installation and ended up in a blank screen. Is there any possibilty to install these updates or is there no necessitiy anymore?

Kind Regards
Peter