Issue: ErrorException: Undefined variable: sub_options - vault/core/controller/ui/watch/vw.php

Stack Trace
#0 /var/www/html/vault/core/controller/ui/watch/vw.php(218): XenForo_Application::handlePhpError(8, 'Undefined varia...', '/var/www/html/v...', 218, Array)
#1 /var/www/html/library/vw/XenForo/DataWriter/User.php(88): vw_UI_Watch_Controller->update_prefs('vw_')
#2 /var/www/html/library/XenForo/DataWriter.php(1423): vw_XenForo_DataWriter_User->_postSave()
#3 /var/www/html/library/XenForo/ControllerPublic/Account.php(766): XenForo_DataWriter->save()
#4 /var/www/html/library/Audentio/UIX/ControllerPublic/Account.php(13): XenForo_ControllerPublic_Account->actionPreferencesSave()
#5 /var/www/html/library/vw/XenForo/ControllerPublic/Account.php(81): Audentio_UIX_ControllerPublic_Account->actionPreferencesSave()
#6 /var/www/html/library/XenForo/FrontController.php(351): vw_XenForo_ControllerPublic_Account->actionPreferencesSave()
#7 /var/www/html/library/XenForo/FrontController.php(134): XenForo_FrontController->dispatch(Object(XenForo_RouteMatch))
#8 /var/www/html/index.php(13): XenForo_FrontController->run()
#9 {main}
Request State
array(3) {
  ["url"] => string(54) "https://www.theexpanse-rp.com/account/preferences-save"
  ["_GET"] => array(0) {
  }
  ["_POST"] => array(18) {
    ["style_id"] => string(1) "0"
    ["language_id"] => string(1) "1"
    ["timezone"] => string(13) "Europe/London"
    ["enable_rte"] => string(1) "1"
    ["enable_flash_uploader"] => string(1) "1"
    ["content_show_signature"] => string(1) "1"
    ["visible"] => string(1) "1"
    ["activity_visible"] => string(1) "1"
    ["uix_sticky_navigation"] => string(1) "1"
    ["uix_sticky_userbar"] => string(1) "1"
    ["uix_sticky_sidebar"] => string(1) "1"
    ["uix_collapse_user_info"] => string(1) "1"
    ["uix_collapse_signature"] => string(1) "1"
    ["_xfToken"] => string(8) "********"
    ["save"] => string(12) "Save Changes"
    ["_xfRequestUri"] => string(26) "/threads/slipping-away.19/"
    ["_xfNoRedirect"] => string(1) "1"
    ["_xfResponseType"] => string(4) "json"
  }
}