[BUG] Claude code can no longer be installed or updated using native installer on IPV6-only networks

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

[!NOTE] Version note: I cannot confirm "latest version" because this bug blocks updating on my machine. Installed version: 2.1.119. This is a server-side/infrastructure issue, independent of client version. The version I run has no bearing on whether downloads.claude.ai publishes an AAAA record.

Updating claude using claude update fails with the following on a machine connected to an IPV6-only network:

Checking for updates to latest version...
Error: Failed to install native update
Error: Failed to fetch version from https://downloads.claude.ai/claude-code-releases/latest: ECONNREFUSED

This is due to there not being a AAAA record for downloads.claude.ai anymore:

dig AAAA downloads.claude.ai 

; <<>> DiG 9.18.39-0ubuntu0.24.04.5-Ubuntu <<>> AAAA downloads.claude.ai
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 36677
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;downloads.claude.ai.           IN      AAAA

;; AUTHORITY SECTION:
claude.ai.              1627    IN      SOA     isla.ns.cloudflare.com. dns.cloudflare.com. 2406270842 10000 2400 604800 1800

;; Query time: 4 msec
;; SERVER: 127.0.0.53#53(127.0.0.53) (UDP)
;; WHEN: Fri Jun 12 11:57:08 UTC 2026
;; MSG SIZE  rcvd: 110
````

Trying to install claude fresh using the native installer at `https://claude.ai/install.sh` *also fails* , because that's a 302 to `https://downloads.claude.ai/claude-code-releases/bootstrap.sh`. 

I'm pretty sure this used to work before. 

### What Should Happen?

There should be an AAAA record for `downloads.claude.ai`.

### Error Messages/Logs

```shell
claude update
Current version: 2.1.119
Checking for updates to latest version...
Error: Failed to install native update
Error: Failed to fetch version from https://downloads.claude.ai/claude-code-releases/latest: ECONNREFUSED
Try running "claude doctor" for diagnostics


curl -fsSL https://claude.ai/install.sh
curl: (7) Failed to connect to downloads.claude.ai port 443 after 2 ms: Couldn't connect to server


 dig AAAA downloads.claude.ai

; <<>> DiG 9.18.39-0ubuntu0.24.04.5-Ubuntu <<>> AAAA downloads.claude.ai
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 62251
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;downloads.claude.ai.           IN      AAAA

;; AUTHORITY SECTION:
claude.ai.              1613    IN      SOA     isla.ns.cloudflare.com. dns.cloudflare.com. 2406270842 10000 2400 604800 1800

;; Query time: 1 msec
;; SERVER: 127.0.0.53#53(127.0.0.53) (UDP)
;; WHEN: Fri Jun 12 12:04:32 UTC 2026
;; MSG SIZE  rcvd: 110

Steps to Reproduce

1. Provision any machine with only IPV6 connectivity (e.g. Hetzner box without ipv4 address)
2. Run claude update or try to install using the native installer at https://claude.ai/install.sh

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.119

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_