Maintenance for the week of March 9:
• [COMPLETE] ESO Store and Account System for maintenance – March 11, 9:00AM EDT (13:00 UTC) - 1:00PM EDT (17:00 UTC)
ESO+ doesn’t include new chapters, although the previous year’s chapter gets rolled into ESO+ when the newest chapter releases. So if you are willing to wait for a year and you’re still a member of ESO+, you will then have access to High Isle (probably…that is how it has worked before, at least).