Hello Maintainer:
Came across this as well and did some digging to find the cause. Found that Python 3.9 removed the getiterator attribute and replaced it with iter. To fix, in file "/usr/lib/python3/dist-packages/catfish_lib/Builder.py" at line 87 changed this line: ele_widgets = tree.getiterator("object") to ele_widgets = tree.iter("object") Also found one more line in the file needed to be changed (as I scanned to see if "getiterator" was mentioned anywhere else in the file) and it's this code at line 112: ele_signals = tree.getiterator("signal") Changed it to show: ele_signals = tree.iter("signal") Saved the original with .orig extension then saved changed file as Builder.py. Tested catfish again from terminal and it started right up and functioned normally as I tested several searches. As I never did a patch diff before, if anyone can create a patch from my notes here feel free to do so. Cheers! -R