The renewal of the SSL is a formality (someone just needs to submit some documentation) or there is a cost involved?
The certificate was signed by Let's Encrypts, which provides the service for free thanks to automated verifications and large tech company support.
Depending on how it was configured on the server of phereo, it could be as simple as running a command, or something more time consuming (stop the server, run the challenge, copy the new files, restart the server...). Anyhow, it has to be done by the maintainer.
On Stereopix, I configured this to be fully automated and managed by the server itself [it took some efforts to make it work fine autonomously], so that I do not forget to renew it every 2 or 3 months, even if Let's Encrypts sends mails a few days before the expiration date.
I hope so.