Elventure not compiling

I’ve downloaded elventure code and it does not compile.

The first problem was prog_uchar which arduino doesnt use anymore. I changed it to const unsigned char.

After that i get this error.

In file included from display.cpp:5:0:
display.h:7: error: variable or field ‘updateDisplay’ declared void
void updateDisplay(Elf elf);
^
display.h:7: error: ‘Elf’ was not declared in this scope
display.cpp:12: error: variable or field ‘updateDisplay’ declared void
void updateDisplay(elf ELF)
^
display.cpp:12: error: ‘elf’ was not declared in this scope
variable or field ‘updateDisplay’ declared void

I dont have enough experience with arduino to be able to solve this problem on my own.
Any help would be appreciated.