Force this option to false. Leaving this as true (currently the default) is dangerous. If the TT-RSS installation upgrades itself to a newer version requiring a schema update, the installation will break the next time the TT-RSS systemd service is restarted. Ideally, the installation itself should be immutable (see https://github.com/NixOS/nixpkgs/issues/55300).
*** NixOS *** NixOS is a Linux distribution based on the purely functional package management system Nix. More information can be found at http://nixos.org/nixos and in the manual in doc/manual.