**TL;DR: Yes — you need to pick a new tariff before 28 November 2026**, or you'll be moved to a more expensive one.

Key points:
- Your current tariff (Fixed Saver 24) ends on 31 December 2026.
- Your rate is currently **24.6p/kWh**; the default you'd be switched to (Standard Variable) is **34.1p/kWh** — about 38% higher.
- **Action needed:** Log into your online account or app and choose a new tariff (e.g., Fixed Saver 27) **before 28 November 2026** if you want to stay on a fixed price.
- Some other terms & conditions change on 1 Jan 2027 (meter readings, complaints, email contact) — nothing to do there.

While you're at it, it's worth comparing Fixed Saver 27 against other suppliers' fixed deals before committing, since the letter doesn't say what Fixed Saver 27's rate is.