GnuCash not displaying "printable invoice" or other reports

GnuCash not displaying "printable invoice" or other reports
It was suggest that I run " WEBKIT_DISABLE_COMPOSITING_MODE=1 gnucash " in the terminal. The terminal responded with " Command 'gnucash' not found, but can be installed with: sudo apt install gnucash " I then ran " sudo apt install gnucash " and it installed gnucash 4.8 ... I am running version 5.8 ... Any suggestions?