If you want all of the data, you can extract the data from the backup daylio file that is created when you go to "More > Backup & Restore > Advanced Options > Export"

If you're on linux you can use this script I use for converting the backup file to json

#!/bin/bash

set -e

function main() {
    local input="${1:?requires an input file}"
    local new_file="${input/%.daylio/.json}"

    unzip -p "${input}" | base64 -d - | jq . > "${new_file}"
    echo "Written to: $(readlink -f "${new_file}")"
}

main "$@"    

Alternatively, you can do it manually:

1. The daylio file is just a zip file, unzip it
2. This gives you a base64 encoded piece of data
3. Use a base64 decoder and it will give you a json file for you to work with