add note to readme

README.md

@@ -198,7 +198,7 @@ It is highly recommended you set the following environment values before startin
 | OLD_BACKUP_DAYS    | How many days to keep backups                                                                                                                                                                       | 30             | any positive integer                                                                                       |
 | AUTO_UPDATE_CRON_EXPRESSION  | Setting affects frequency of automatic updates. | 0 \* \* \* \* | Needs a Cron-Expression - See [Configuring Automatic Backups with Cron](#configuring-automatic-backups-with-cron) |
 | AUTO_UPDATE_ENABLED | Enables automatic updates | false | true/false |
-| AUTO_UPDATE_WARN_MINUTES | How long to wait to update the server, after the player were informed. | 30 | !0 |
+| AUTO_UPDATE_WARN_MINUTES | How long to wait to update the server, after the player were informed. (This will be ignored, if no Players are connected) | 30 | !0 |
 | AUTO_REBOOT_CRON_EXPRESSION  | Setting affects frequency of automatic updates. | 0 0 \* \* \* | Needs a Cron-Expression - See [Configuring Automatic Backups with Cron](#configuring-automatic-reboots-with-cron) |
 | AUTO_REBOOT_ENABLED | Enables automatic reboots | false | true/false |
 | AUTO_REBOOT_WARN_MINUTES | How long to wait to reboot the server, after the player were informed. | 5 | !0 |