The Claude 4 deprecation is 5 days away. If you've been putting off your migration, this FAQ answers every question you have — from "which models are affected" to "how do I update my LangChain code." Bookmark this page and check off each answer as you go.
Quick Answers — The TL;DR
Here are the five questions developers ask most, answered in 30 seconds or less:
Q: When does Claude 4 shut down?
June 15, 2026. No extensions. No grace period. After that date, all Claude 4 Opus and Claude 4 Sonnet API calls return errors immediately.
Q: Which models are affected?
Claude 4 Opus and Claude 4 Sonnet only. Claude Opus 4.8, Claude Sonnet 4.6, and Claude Haiku 4.5 are NOT affected — these are newer models that will continue working.
Q: Will my API calls fail?
Yes. After June 15, any request using claude-4-opus or claude-4-sonnet will return a 404 error. There is no fallback mode.
Q: What should I migrate to?
Claude Opus 4.8 ($5/$25, 67% cheaper), Claude Sonnet 4.6 ($3/$15, same price, 5x context), or budget alternatives like DeepSeek V4 Pro ($0.435/$0.87, 97% cheaper). Use the APIpulse calculator for your exact savings.
Q: How do I migrate?
Change the model ID in your code. The API format is identical. Replace claude-4-opus with claude-opus-4-8, or claude-4-sonnet with claude-sonnet-4-6. Test with a few requests, then deploy. Takes about 30 minutes.
Detailed FAQ — Everything You Need to Know
What exactly is being deprecated?
Two model variants are shutting down: Claude 4 Opus ($15/M input, $75/M output, 200K context) and Claude 4 Sonnet ($3/M input, $15/M output, 200K context). The API infrastructure itself is not shutting down — only these specific model IDs will stop returning results. All other Anthropic models remain fully operational.
Which API endpoints are affected?
All endpoints that accept a model parameter are affected. If your request specifies claude-4-opus or claude-4-sonnet as the model, it will fail. This includes the Messages API, any streaming endpoints, and third-party integrations that route to these model IDs.
Is there a grace period?
No. There is no grace period, no partial deprecation, and no extension. The shutdown is hard: on June 15, 2026, Claude 4 Opus and Claude 4 Sonnet stop working immediately. This was communicated months in advance to give developers time to migrate.
Can I still use Claude 4 after June 15?
No. After June 15, any API call to Claude 4 Opus or Claude 4 Sonnet will fail with an error. If you need Claude-quality output, migrate to Claude Opus 4.8 or Claude Sonnet 4.6 — these are the official successors with the same API format and better performance.
What's the cost difference between Claude 4 and replacements?
The savings are significant depending on which replacement you choose:
- Claude 4 Opus ($15/$75) → Claude Opus 4.8 ($5/$25): 67% savings
- Claude 4 Sonnet ($3/$15) → Claude Sonnet 4.6 ($3/$15): Same price, 5x more context
- DeepSeek V4 Pro ($0.435/$0.87): 97% cheaper
- Llama 4 Maverick ($0.27/$0.85): 98% cheaper, open source
- Gemini 2.5 Pro ($1.25/$10): 92% cheaper on output
What about fine-tuned Claude 4 models?
Fine-tuned Claude 4 models will also stop working after June 15. You will need to re-fine-tune on the successor models (Opus 4.8 or Sonnet 4.6) if you had custom fine-tunes. Contact Anthropic support for guidance on transferring fine-tuned weights to the new models.
How do I update my LangChain / LlamaIndex code?
In LangChain, update the model string in your ChatAnthropic instantiation: change model='claude-4-opus' to model='claude-opus-4-8'. In LlamaIndex, update the model parameter in your LLM class. Both libraries use the same underlying Anthropic SDK, so only the model ID needs to change — no other code modifications required.
What if I'm using Claude 4 via a third-party service?
If you use Claude 4 via OpenRouter, Amazon Bedrock, or another third-party provider, you need to update your model ID in that provider's configuration. Some third-party providers may have already removed Claude 4 from their available models list. Check with your provider for their specific migration timeline.
Will Claude 4 documentation stay available?
Anthropic typically keeps documentation for deprecated models available for reference, but it may be moved to an archive section. The API references and migration guides for the successor models (Opus 4.8, Sonnet 4.6) will be the primary documentation going forward.
What's the recommended migration order?
Follow these steps in order:
- Audit your codebase for all
claude-4-opusandclaude-4-sonnetreferences - Test migration to Claude Opus 4.8 or Sonnet 4.6 in development
- Deploy to staging and verify everything works
- Monitor production error rates after deploying
- Update cost tracking and budget alerts for the new pricing
Most teams complete this in 30 minutes to 2 hours depending on codebase size.
Migration Cost Calculator
See exactly how much you'll save based on your current Claude 4 usage:
At 10M input + 1M output tokens per month, here's your monthly bill with each option:
- Claude 4 Opus: $225/month
- Claude Opus 4.8: $75/month (save $150)
- DeepSeek V4 Pro: $5.22/month (save $219.78)
- Llama 4 Maverick: $3.55/month (save $221.45)
Calculate Your Exact Savings
Plug in your real usage numbers and see what each alternative costs for your specific workload.
Open Cost Calculator →Step-by-Step Migration Guide
The migration itself is straightforward — change the model ID, test, deploy. Here's the code:
Python (Anthropic SDK)
# Before (Claude 4 — will break after June 15)
import anthropic
client = anthropic.Anthropic()
response = client.messages.create(
model="claude-4-opus-20250415", # DEPRECATED
max_tokens=4096,
messages=[{"role": "user", "content": "Hello"}]
)
# After (Claude Opus 4.8 — direct successor)
import anthropic
client = anthropic.Anthropic()
response = client.messages.create(
model="claude-opus-4-8-20250601", # ACTIVE
max_tokens=4096,
messages=[{"role": "user", "content": "Hello"}]
)Node.js (Anthropic SDK)
// Before
const response = await anthropic.messages.create({
model: "claude-4-opus-20250415", // DEPRECATED
max_tokens: 4096,
messages: [{ role: "user", content: "Hello" }]
});
// After
const response = await anthropic.messages.create({
model: "claude-opus-4-8-20250601", // ACTIVE
max_tokens: 4096,
messages: [{ role: "user", content: "Hello" }]
});For a comprehensive migration checklist, code examples for every provider, and a decision tree for choosing your replacement, visit the Claude 4 Migration Command Center.
For interactive model comparison and code diff generation, try the Claude 4 Migration Tool.
Track the shutdown in real time
APIpulse Pro monitors model availability, tracks your migration progress, and alerts you if your code is still calling deprecated endpoints.
Don't Get Caught Off Guard
5 days is enough time to migrate properly — but only if you start now. Use the Command Center for a guided walkthrough.
Open Migration Command Center →