feat: update minimal supported version of Node.js to v20 #638

bliuchak · 2026-01-12T16:29:38Z

This PR upgrades minimal supported version of Node.js to v20.

Why Node.js 20?

I think for us it makes sense to support last 3 LTS versions of node. As of today they are: 24, 22 and 20.

Also I'll keep tests at Github Actions for Node.js 16, 18 and 20 (will be added) to make sure we're not breaking too much things. At least right now. However this might change in next major release.

Migration Flow

Migration from Node.js 18 to 20 wasn't complicated. Here are the main issues which we've faced:

Node.js 20 enables keep-alive by default. This should be turned off in tests explicitly.
Some tests should be skipped since Node.js became more strict 👍
For anonymized proxy script Node.js 20 throw socket hang up instead of ECONNREFUSED for some special cases

Skipped Tests On Node.js 20

Overview

There was 2242 tests cases for Node.js v18. Currently there are 2191 (minus 51 test case) for Node.js v20. See details below:

"ignores non-standard server HTTP headers" - Skipped when !useUpstreamProxy:
- Main proxy configurations: 2 (http/https) × 2 (ssl) × 4 (auth) = 16 configs
- Custom response suites: 2 x 2 x 4 = 16 configs
- Direct tests (HTTP/HTTPS -> Target): 2 configs
- Total: 34 tests
"gracefully fails on invalid HTTP status code" - Skipped when !useUpstreamProxy && !useSsl:
- Main proxy configurations: 2 x 1 x 4 = 8 configs
- Custom response suites: 2 x 1 x 4 = 8 configs
- Direct tests: 1 config (HTTP -> Target only)
- Total: 17 tests

Grand total: 34 + 17 = 51 skipped tests

Why these tests are skipped

Both tests verify the proxy's behavior when receiving malformed HTTP responses from upstream servers:

"ignores non-standard server HTTP headers" - tests handling of headers with spaces in names (e.g., Invalid Header With Space: value) which violate HTTP RFC
"gracefully fails on invalid HTTP status code" - tests handling of invalid status codes (like HTTP/1.1 55 OK)

In Node.js 20, the --insecure-http-parser flag no longer relaxes HTTP client parsing for these edge cases. The HTTP client throws parse errors before the proxy can even process them. This is a Node.js security hardening change, not a proxy bug.

Close #601

Copilot

Pull request overview

This PR upgrades the minimal supported Node.js version from v14 to v20 to align with active LTS versions (20, 22, 24) and address the Node.js 18 end-of-life. The upgrade addresses Node.js 20's stricter HTTP parsing and default keep-alive behavior changes.

Changes:

Updated minimum Node.js version requirement from >=14 to >=20
Disabled HTTP keep-alive across test servers to prevent connection tracking issues
Added logic to skip 51 tests on Node.js 20+ that rely on lenient HTTP parsing
Updated error message handling for connection failures to account for Node.js 20 behavior changes

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
package.json	Updated engines.node requirement from >=14 to >=20
.github/workflows/check.yaml	Updated test matrix to Node.js 16, 18, 20 and changed lint condition to run on Node 20
test/Dockerfile	Updated base Docker image from Node 18.20.8 to Node 20.19.6
test/utils/target_server.js	Disabled keep-alive on HTTP test server by setting keepAliveTimeout to 0
test/server.js	Added Connection: 'close' header to test requests and disabled keep-alive on proxy servers; added Node.js version check to skip tests for stricter HTTP parsing
test/https-stress-test.js	Disabled keep-alive on global HTTP agent and proxy server
test/anonymize_proxy.js	Updated error assertion to accept both 'ECONNREFUSED' and 'socket hang up' messages
test/anonymize_proxy_no_password.js	Updated error assertion to accept both 'ECONNREFUSED' and 'socket hang up' messages

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jirimoravcik · 2026-01-13T08:32:32Z

.github/workflows/check.yaml

    strategy:
      matrix:
-        node-version: [14, 16, 18]
+        node-version: [16, 18, 20]


Why are we running checks on unsupported Node.js versions? Shouldn't this be [20, 22, 24]?

Good point. For some reason I kept this because all tests passed. But, you're probably right to drop old versions.

danpoletaev

Looks good!

Left few suggestions that needs to be reviewed before merging

danpoletaev · 2026-01-13T09:10:44Z

package.json

    },
    "engines": {
-        "node": ">=14"
+        "node": ">=20"


Shouldn't minimal node version be 16?
It should just warn user to use node 20, right?

Let's also update @types/node

The idea was to set minimal engine version to current oldest supported LTS version of Node. As of today it's Node 20.

Node 18 both active and security support period has ended.

Let's also update @types/node

Good point. Upgraded.

danpoletaev · 2026-01-13T09:27:43Z

test/Dockerfile

@@ -1,4 +1,4 @@
-ARG NODE_IMAGE=node:18.20.8-bookworm
+ARG NODE_IMAGE=node:20.19.6-bookworm


We need to also update scripts/test-docker-all.sh, since there're hardcoded node versions

You're right. Gonna fix this.

feat: update minimal supported version of Node.js to v20

dea1e06

Close #601

bliuchak requested review from Copilot, danpoletaev, jirimoravcik and lewis-wow January 12, 2026 16:29

github-actions bot assigned bliuchak Jan 12, 2026

github-actions bot added this to the 132nd sprint - Core Services team milestone Jan 12, 2026

github-actions bot added t-core-services Issues with this label are in the ownership of the core services team. tested Temporary label used only programatically for some analytics. labels Jan 12, 2026

Copilot started reviewing on behalf of bliuchak January 12, 2026 16:30 View session

Copilot AI reviewed Jan 12, 2026

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jirimoravcik approved these changes Jan 13, 2026

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danpoletaev requested changes Jan 13, 2026

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github-actions bot added t-core-services Issues with this label are in the ownership of the core services team. tested Temporary label used only programatically for some analytics. labels Jan 13, 2026

bliuchak added 3 commits January 13, 2026 22:49

fix: apply editorconfig ident value

50810dc

fix: run tests only on 20, 22 and 24 node versions

ff188a2

fix: adjust test error message due to diff between 20 vs 22+

2a0cb36

bliuchak added adhoc Ad-hoc unplanned task added during the sprint. and removed adhoc Ad-hoc unplanned task added during the sprint. t-core-services Issues with this label are in the ownership of the core services team. labels Jan 13, 2026

upgrade types/node to v20 too

05697f7

		@@ -1,4 +1,4 @@
		ARG NODE_IMAGE=node:18.20.8-bookworm
		ARG NODE_IMAGE=node:20.19.6-bookworm

feat: update minimal supported version of Node.js to v20 #638

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bliuchak commented Jan 12, 2026

Why Node.js 20?

Migration Flow

Skipped Tests On Node.js 20

Overview

Why these tests are skipped

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