My first step now when trying to resurrect old projects is to create a Docker container for it - that way I can install any old versions of anything (like node or PHP) I need without having to worry about it polluting anything else on the system.
It wouldn't be suitable for any application where you care about GDPR (i.e. you store personal information and have users in the EU)
The "right to be forgotten" is not compatible with immutable data. You can't simply need to mark data as deleted, you need to 'purge' it from your system (and possible backups, depending on how long you keep historic backups) - that isn't possible in a system with immutable data.
I mean there are solutions for this. About CQRS/Event sourcing I've read that it's possible to solve it by encrypting the data with different keys and then rotating/throwing away the keys every now and then. Seems a bit hacky but probably there are more elegant approaches.
It has a maximum, not a minimum: The higher of 4% turnover OR €20m. That means even with 0 revenue, your fine can be up to €20m (It won't, because if you're not making money your small fry to them, but still, the fine can be greater than 0)
(2^32)÷(1920×1080×4×3×2) = 86