Store the data version for data migrations at some later point

lang/en.json

@@ -11,6 +11,9 @@
 			}
 		},
 		"ui": {
+			"messages": {
+				"unknownVersion": "Smart Doors migration failed with the error: Unkown Version. Please report this to the Smart Doors issue tracker. To prevent possible data loss don't use this plugin until this error is fixed."
+			},
 			"synchronizedDoors": {
 				"description": "State changes of doors in the same synchronization group will be synchronized across scenes. Leave blank to disable synchronization for this door.",
 				"groupName": "Synchronization Group"

main.js

@@ -1,6 +1,7 @@
 "use strict";
 
 const settingsKey = "smart-doors";
+const currentDataVersion = "1.0.0"
 
 Hooks.once("init", () => {
 	registerSettings()
@@ -8,6 +9,10 @@ Hooks.once("init", () => {
 	hookWallConfigUpdate()
 })
 
+Hooks.once("ready", () => {
+	performMigrations()
+})
+
 // Tint the source door red when a locked alert is hovered
 Hooks.on("renderChatMessage", (message, html, data) => {
 	// Tint the door that generated this message
@@ -236,8 +241,24 @@ function synchronizedDoorsRightClick() {
 	return true
 }
 
+function performMigrations() {
+	const dataVersion = game.settings.get(settingsKey, "dataVersion")
+	if (dataVersion === "fresh install")
+	{
+		game.settings.set(settingsKey, "dataVersion", currentDataVersion);
+		return;
+	}
+	if (dataVersion != currentDataVersion)
+		ui.notifications.error(game.i18n.localize("smart-doors.ui.messages.unknownVersion"), {permanent: true})
+}
 
 function registerSettings() {
+	game.settings.register(settingsKey, "dataVersion", {
+		scope: "world",
+		config: false,
+		type: String,
+		default: "fresh install"
+	})
 	game.settings.register(settingsKey, "lockedDoorAlert", {
 		name: "smart-doors.settings.lockedDoorAlert.name",
 		hint: "smart-doors.settings.lockedDoorAlert.hint",