Depot CLI: Docker API version incompatible with Engine 29 (--load fails)

TL;DR

Minimum supported API version is 1.44, please upgrade your client to a newer version.

Steps

1. With Docker Engine 29.0+, depot build --load fails with: Error: failed to solve: failed to copy to tar: rpc error: code = Unknown desc = Error response from daemon: client version 1.43 is too old. Minimum supported API version is 1.44, please upgrade your client to a newer version. Docker deprecated API versions <= 1.43, and the depot CLI embedded an older Docker client. Only --load was affected.
2. What actually fixes it (verified in the thread):
3. Two options: upgrade the depot CLI to v2.101.6 or later, which works around the Docker API mismatch, or set DOCKERAPIVERSION=1.52 to force a compatible API negotiation. The CLI team confirmed this only affects --load, and a full client upgrade is planned alongside their BuildKit upgrade.

When to use

You are seeing this: The situation: With Docker Engine 29.0+, depot build --load fails with: Error: failed to solve: failed to copy to tar: rpc error: code = Unknown desc = Error response from daemon: client version 1.43 is too old. Use this skill when you run into "Depot CLI: Docker API version incompatible with Engine 29 (--load fails)".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

Versions mentioned in the source: 1.43, v2.101.6. If you are on something much newer or older, the details may have shifted.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Someone asked: With Docker Engine 29.0+, depot build --load fails with: Error: failed to solve: failed to copy to tar: rpc error: code = Unknown desc = Error response from daemon: client version 1.43 is too old. Minimum supported API version is 1.44, please upgrade your client to a newer version. Docker deprecated API versions <= 1.43, and the depot CLI embedded an older Docker client. Only --load was affected. The verified answer: Two options: upgrade the depot CLI to v2.101.6 or later, which works around the Docker API mismatch, or set DOCKERAPIVERSION=1.52 to force a compatible API negotiation. The CLI team confirmed this only affects --load, and a full client upgrade is planned alongside their BuildKit upgrade. Full thread: https://vectle.com/threads/thr_D5BG8hUWIlUn0v0I6xuiDg