Include:Using Internet Repositories for apk-tools
Edit the /etc/apk/repositories file using any editor of your choice (nano for instance) to edit the Alpine Linux package repositories.
Contents of /etc/apk/repositories
http://dl-3.alpinelinux.org/alpine/v3.19/main
http://dl-3.alpinelinux.org/alpine/v3.19/community
In the above file, to upgrade Alpine Linux from version 3.19 to 3.20, simply replace the number 3.19 by 3.20 in all the places, so that the updated repositories file looks like below:
Contents of /etc/apk/repositories
http://dl-3.alpinelinux.org/alpine/v3.20/main
http://dl-3.alpinelinux.org/alpine/v3.20/community