Claude Code v2.1.96 — No New Environment Variables: Bedrock Auth Hotfix#
Published on April 8, 2026
Part of the Claude Code Version Tracker series. | Official Env Vars | Official Changelog
Claude Code v2.1.96 is a single-fix patch targeting a Bedrock authentication regression introduced in v2.1.94. No environment variables were added or removed — the binary extraction is byte-identical to v2.1.94. This is the second consecutive hotfix release (v2.1.95 was skipped), confirming that the Mantle auth layer introduced in v2.1.94 is still stabilizing in production.
What Changed#
| v2.1.94 | v2.1.96 | |
|---|---|---|
| Environment variables | 222 | 222 (0 net) |
| Model IDs | 16 | 16 |
| Feature gates | 0 | 0 |
| Dynamic configs | 29 | 29 |
| Slash commands | 24 | 24 |
The Fix#
The changelog[1] describes a single item:
Fixed Bedrock requests failing with
403 "Authorization header is missing"when usingAWS_BEARER_TOKEN_BEDROCKorCLAUDE_CODE_SKIP_BEDROCK_AUTH(regression in 2.1.94)
This directly relates to the Mantle auth stack introduced in v2.1.94 (CLAUDE_CODE_USE_MANTLE, CLAUDE_CODE_SKIP_MANTLE_AUTH, CLAUDE_CODE_USE_ANTHROPIC_AWS, CLAUDE_CODE_SKIP_ANTHROPIC_AWS_AUTH). The new layered auth path appears to have broken the existing bearer-token flow for users who had already configured direct Bedrock access. The fix restores backward compatibility for those credential strategies while keeping the new Mantle layer intact.
What This Tells Us#
The Mantle rollout is production-sensitive. A same-day regression fix (v2.1.94 landed April 7, v2.1.96 landed April 8) for a 403 on the authorization header means real Bedrock users hit this in production. The fact that CLAUDE_CODE_SKIP_BEDROCK_AUTH — itself an escape hatch — was also broken suggests the regression was in the credential resolution pipeline before any skip logic could apply. Enterprise Bedrock deployments are clearly a high-priority path, and the speed of this fix reflects that.
Version skipping continues. v2.1.95 doesn't appear in the changelog, continuing the pattern of occasional version number gaps. These likely correspond to internal builds that didn't pass release gates or were superseded before publication.
Sources#
- Claude Code Official Changelog — v2.1.96 release notes
This analysis is conducted for independent security research and interoperability purposes under fair use principles. All trademarks belong to their respective owners. The information presented here documents publicly observable behavior of installed software and is not intended to circumvent any technological protection measures, infringe on intellectual property rights, or encourage unauthorized use. Use these findings at your own discretion.
Related Versions#
- Claude Code v2.1.94 — 17 New Environment Variables — Mantle auth, agent cost steering, resume controls
- Claude Code v2.1.88 — 7 New Environment Variables — mouse control, REPL mode, flicker-free rendering
- Claude Code v2.1.86 — 2 New Environment Variables — trusted device tokens, OAuth console override
- Claude Code v2.1.85 — 6 New Environment Variables — MCP server config, yoga-layout removal, OAuth endpoint overrides
- Claude Code v2.1.84 — 6 New Environment Variables — idle management, PowerShell tool, Bedrock parity
Related: Context Window Management Guide | Claude Code Productivity Tips | The Agentic Engineering Playbook