First install DEV for the PHP you are using. In my case that would be PLESK PHP 7.1
apt-get install make gcc plesk-php71-dev
Next use PECL to install dbase extension.
/opt/plesk/php/7.1/bin/pecl install dbase-7.0.0beta1
If all goes good, you should see this:
Build process completed successfully
Installing '/opt/plesk/php/7.1/lib/php/modules/dbase.so'
install ok: channel://pecl.php.net/dbase-7.0.0beta1
configuration option "php_ini" is not set to php.ini location
You should add "extension=dbase.so" to php.ini
Last step is to register the extension:
echo "extension=dbase.so" > /opt/plesk/php/7.1/etc/php.d/dbase.ini
plesk bin php_handler --reread