Raspberry OS: add-apt-repository: not found

[cerebrux]

When installing or updating on Raspberry OS:

Adding Utappia repository
/var/lib/dpkg/info/ucaresystem-core.postinst: 34: add-apt-repository: not found
dpkg: error processing package ucaresystem-core (--configure):
 installed ucaresystem-core package post-installation script subprocess returned error exit status 127
Errors were encountered while processing:
 ucaresystem-core
E: Sub-process /usr/bin/dpkg returned an error code (1)