Problems with an old library 2013 but with an important modification

[EMI2-2]

Hi, I had an old library running about ten years ago, but it has a modification that works with my shutters.

I found the modification at: http://physudo-e.blogspot.com/2013/08/home-automation-with-arduino-and-433_16.html http://physudo-e.blogspot.com/2013/08/home-automation-with-arduino-and-433.html

The problem, is that now I have tried to compile the code again and I get this error: RCSwitch.cpp:325:12: error: invalid conversion from 'char' to 'char*' [-fpermissive] 325 | return '0';

I don't understand why the old library doesn't work, and the new libraries have changed so much that I don't know how to add the modifications.

Could someone help me? RCSwitch.zip