it is changed in compile time

we can't change module attributes and endpoint settings in runtime

lib/pleroma/config/transfer_task.ex

@@ -0,0 +1,41 @@
+defmodule Pleroma.Config.TransferTask do
+  use Task
+  alias Pleroma.Web.AdminAPI.Config
+
+  def start_link do
+    load_and_update_env()
+    if Pleroma.Config.get(:env) == :test, do: Ecto.Adapters.SQL.Sandbox.checkin(Pleroma.Repo)
+    :ignore
+  end
+
+  def load_and_update_env do
+    if Pleroma.Config.get([:instance, :dynamic_configuration]) do
+      Pleroma.Repo.all(Config)
+      |> Enum.each(&update_env(&1))
+    end
+  end
+
+  defp update_env(setting) do
+    try do
+      key =
+        if String.starts_with?(setting.key, "Pleroma.") do
+          "Elixir." <> setting.key
+        else
+          setting.key
+        end
+
+      Application.put_env(
+        :pleroma,
+        String.to_existing_atom(key),
+        Config.from_binary(setting.value)
+      )
+    rescue
+      e ->
+        require Logger
+
+        Logger.warn(
+          "updating env causes error, key: #{inspect(setting.key)}, error: #{inspect(e)}"
+        )
+    end
+  end
+end