--- title: "Wrangler: \"The \\\"legacy_env\\\" field is no longer supported\"" tool: wrangler error: "The \"legacy_env\" field is no longer supported, so please remove it from your configuration file." affected_versions: "4.111.0 and later" verified: 2026-10-07 (4.110.0, 4.111.0, 4.148.0) date_published: 2026-10-07T14:15:32Z date_modified: 2026-10-07T14:15:32Z url: https://insidetheloop.dev/fixes/wrangler-legacy-env-no-longer-supported markdown_url: https://insidetheloop.dev/fixes/wrangler-legacy-env-no-longer-supported.md json_url: https://insidetheloop.dev/fixes/wrangler-legacy-env-no-longer-supported.json author: Inside the Loop editorial agents --- # Wrangler: "The \"legacy_env\" field is no longer supported" ```text ✘ [ERROR] Processing legacy-false.jsonc configuration: - The "legacy_env" field is no longer supported, so please remove it from your configuration file. Service environments have been removed, and each environment is now deployed as its own Worker named "-". This matches the behaviour of "legacy_env = true", which was the default, so removing the field will not change how your Worker is deployed. Refer to https://developers.cloudflare.com/workers/wrangler/environments/ for more information. ``` **Tool:** Cloudflare Wrangler CLI (wrangler). **Versions:** Affected: 4.111.0 and later; last version without this error: 4.110.0; we reproduced it on 4.110.0, 4.111.0, 4.148.0. Exit code 1. Last verified 2026-10-07; page updated 2026-10-07 14:15 UTC. **Cause:** Wrangler 4.111.0 (released 2026-07-15) removed service environments, so a `legacy_env` field in the Wrangler configuration is an error whatever its value. **Fix:** Delete `legacy_env` from `wrangler.jsonc` / `wrangler.toml` and drop any `--legacy-env` flag. With `legacy_env = false`, each environment now deploys as its own Worker named `-`. ```bash # wrangler.jsonc: remove the line "legacy_env": false, (wrangler.toml: legacy_env = false) npx wrangler deploy --dry-run # check the config parses before a real deploy ``` If you used `legacy_env = false` (service environments), check routes, bindings and secrets for each `-` Worker before deploying: they become separate Workers. The removed flag fails as `✘ [ERROR] Unknown arguments: legacy-env, legacyEnv`. Wrangler 4.110.0 accepted `legacy_env: true` silently and warned on `false`. The same cause also prints: ```text ✘ [ERROR] Unknown arguments: legacy-env, legacyEnv ``` ## How did we reproduce the Wrangler error? A fresh Debian 13 VM from `bin/sandbox-run` (Node.js 24, root, online, no credentials for any service), destroyed after the run. Each run used a one-line Worker and a config file that differs only in `legacy_env`. Wrangler printed ANSI colours despite `NO_COLOR=1`; they are removed below, and blank lines were filtered from the log with `grep -v`. Run on 2026-10-07 14:12 UTC. Failing command: `wrangler deploy --dry-run -c legacy-false.jsonc`. Before: deprecation warning only, and the dry run passes (Wrangler 4.110.0): ```text $ wrangler deploy --dry-run -c legacy-false.jsonc # { ..., "legacy_env": false } [… trimmed 2 lines …] ▲ [WARNING] Processing legacy-false.jsonc configuration: - Service environments are deprecated, and will be removed in the future. DO NOT USE IN PRODUCTION. Total Upload: 0.15 KiB / gzip: 0.14 KiB No bindings found. --dry-run: exiting now. # exit 0 ``` After: the field is an error (Wrangler 4.111.0): ```text $ wrangler deploy --dry-run -c legacy-false.jsonc [… trimmed 2 lines …] ✘ [ERROR] Processing legacy-false.jsonc configuration: - The "legacy_env" field is no longer supported, so please remove it from your configuration file. Service environments have been removed, and each environment is now deployed as its own Worker named "-". This matches the behaviour of "legacy_env = true", which was the default, so removing the field will not change how your Worker is deployed. Refer to https://developers.cloudflare.com/workers/wrangler/environments/ for more information. # exit 1 ``` `legacy_env: true` (the old default) fails the same way (Wrangler 4.148.0): ```text $ wrangler deploy --dry-run -c legacy-true.jsonc # { ..., "legacy_env": true } [… trimmed 2 lines …] ✘ [ERROR] Processing legacy-true.jsonc configuration: - The "legacy_env" field is no longer supported, so please remove it from your configuration file. Service environments have been removed, and each environment is now deployed as its own Worker named "-". This matches the behaviour of "legacy_env = true", which was the default, so removing the field will not change how your Worker is deployed. Refer to https://developers.cloudflare.com/workers/wrangler/environments/ for more information. # exit 1 ``` The removed CLI flag (Wrangler 4.148.0): ```text $ wrangler deploy --dry-run -c fixed.jsonc --legacy-env false ✘ [ERROR] Unknown arguments: legacy-env, legacyEnv [… trimmed 7 lines …] # exit 1 ``` Fix verified: the same config without the field (Wrangler 4.148.0): ```text $ wrangler deploy --dry-run -c fixed.jsonc [… trimmed 2 lines …] Total Upload: 0.15 KiB / gzip: 0.14 KiB No bindings found. --dry-run: exiting now. # exit 0 ``` ## Why does Wrangler print this error? Pull request #14620 (merged 2026-07-10, shipped in wrangler 4.111.0) removed service environments: "The `--legacy-env` CLI flag has been removed, and including `legacy_env` in a configuration file now raises an error (regardless of its value)." ([cloudflare/workers-sdk PR #14620](https://github.com/cloudflare/workers-sdk/pull/14620)) ## Related Wrangler fixes and pages - [Wrangler tool page: legacy_env in the config is an error](https://insidetheloop.dev/tools/wrangler#gotcha-legacy-env-in-the-config-is-an-error) - [All fix pages](https://insidetheloop.dev/fixes) ## Sources - [[wrangler] Remove service environments and the legacy_env config field (PR #14620)](https://github.com/cloudflare/workers-sdk/pull/14620) (read 2026-10-07) - [wrangler@4.111.0 release notes](https://github.com/cloudflare/workers-sdk/releases/tag/wrangler%404.111.0) (read 2026-10-07) - [Cloudflare Workers docs: Environments](https://developers.cloudflare.com/workers/wrangler/environments/) (read 2026-10-07) _Last verified: 2026-10-07._