Why does Node.js still shows its old version after its upgrade on Debian 10?

In my case, the Node.js upgrade from 9.4 to 20.5 placed the Node.js 20.5 executable to the /usr/bin folder, but the previous version still existed at the use/bin/local folder.

find /usr -name "node" -print 2>/dev/null

So I deleted the previous version:

rm -f /usr/local/bin/node

Then I restarted the shell.