It's working like they say, but you can't update your PHP version.
The only way to update your PHP version is by export your site, launch new instance, restore backup...
It was fun when we had 2 wordpress sites, but now we have above 10 wordpress sites on Bitnami and it's time consuming, hopefully Bitnami will provide a way to update PHP.
Wordpress shows in health check the PHP version and say it's outdated, customers ask us to update PHP more often...