21 Releases Behind: I Rebuilt Instead of Upgrading

Description and use

The article explains why the author chose to rebuild Home Assistant from scratch instead of upgrading an instance 21 releases behind, detailing the risks, costs, and parallel operation of the old system.

Problem

Running Home Assistant 21 releases behind without upgrading, risking accumulated state and configuration complexity.

Outcome

Rebuilding avoided upgrade failure risk but required re‑creating 751 entities, losing two years of recorder data and tuned automations.

Workflow

• 1. Decided not to upgrade after reviewing instance state via REST API.
• 2. Chose to rebuild on a new machine instead of upgrading.
• 3. Started fresh Home Assistant install, noting default country, language selector, and three areas.
• 4. Planned to rebuild configuration by recreating entities and automations.
• 5. Continued running old instance while new machine was being set up.
• 6. Awaited new machine to become useful before cutover.

Evidence

The Home Assistant that runs my house is on 2024.11.1, released in November 2024. The current version is 2026.8.2. That is roughly 21 monthly releases of distance, and it has been running the whole time without complaining.

Source

Before deciding anything I checked what was actually in there, against the running instance's own REST API rather than from memory: 751 entities, 150 components, no themes at all.

Source

I decided against upgrading before trying it.

Source

The old instance runs from a plain docker run with no compose file, so there is no single document describing how it starts.

Source

The part I underestimated is that a rebuild means dealing with all 751 entities again, one way or another.

Source

Two years of recorder data stays with the old instance, so every long‑run statistic starts from zero on the new one — energy totals, temperature trends, anything with a graph behind it.

Source

The new build binds no device in its first phase. The old instance continues to run the house, untouched, which is the only reason this was a comfortable decision at all.

Source