I just wanted to confirm that uploading these two files has indeed fixed the incompatibility issues as the code works as expected now and without reporting any errors
once again, thanks a lot for the support!

thank you all for the support!
I suspected the version number may be too low for this code too work

since updating from 1.0.5.0 to 1.0.5.1 is a rather big step and my shop is currently quite heavily customised, I'll first try to copy these two files and see if it needs anything else (hopefully not)