I've been putting off upgrading from Mojave 10.14 to Catalina as I know I have at least one paid-for 32-bit app which doesn't offer a free upgrade.
This question talks about manually detecting 32-bit apps prior to installation: How can I find out which Mac apps are 32-bit?
But I wondered, when Catalina is installed will it check for such apps and warn me they won't be usable? Further, will it tidy up by removing such apps or will I end up with non-runnable apps to manually clean up?