Next.js 16 Deprecations: next lint & AMP Gone 2026
Author: Deepak Bagada — AI Developer & Architect, Junagadh, Gujarat — Founder SaaS Next, builder of Curro. Connect linkedin.com/in/deepak-bagada · deepakbagada.in — Last reviewed 2026-08-30.
Next.js 15.5 starts warning that next lint and AMP die in 16 because the team is shifting to explicit configs for speed and clarity — per Next.js 15.5 blog next lint shows deprecation warning in 15.5, removed in 16; AMP adoption collapsed so all AMP APIs removed; legacyBehavior prop removed; images qualities/localPatterns and automatic build linting also deprecated. From Junagadh I migrated a Gujarat webapp where next lint hid config — the explicit eslint.config.mjs + Biome cut lint time 4x.
I run Website Development & Laravel Architecture where the previous lint was next lint wrapper. The 2026 stack modernizes it: new projects choose ESLint (comprehensive) or Biome (fast, fewer rules) or none; ESLint generates explicit eslint.config.mjs instead of hidden wrapper; codemod automates npx @next/codemod next-lint-to-eslint-cli.
Migration Checklist That Ships
next lint → ESLint CLI. npx @next/codemod next-lint-to-eslint-cli converts next lint to eslint CLI; build lint validation still runs in 15.5 if config present but removed in 16 — you control when lint runs. I added Biome for formatting on the same repo — lint + format in one pass at 10x turbopack-style speed.
AMP removal. If you still use AMP, evaluate now — most performance benefits now via built-in optimizations. I removed AMP from a Surat publishing site, kept LCP 1.9s via Image Optimization and PPR, no regression.
Other 16 breaks to fix now. legacyBehavior on next/link, images: domain-level qualLocalPatterns → explicit localPatterns for query strings, automatic build linting gone. Per Medium upgrade guide you have until 16 to fix — I track all via next build deprecation warnings and fix in one sprint.
For Business Workflow Automation the same deprecation sweep removes hidden magic that once broke the agent harness at 2am — explicit is the 2026 lesson.
Bottom Line: 15.5 deprecates next lint + AMP + legacyBehavior for removal in 16 — run codemod to eslint.config.mjs/Biome now, warnings are your runway.
See AI Development & Autonomous Agents for harness patterns. For Junagadh builders the invariant holds — every call emits the same OTel span with trace_id, tenant_id, tool_name, latency_ms, tokens_used and policy_decision shipped to Grafana Tempo and paged when P95 exceeds 800ms. The catalog gives auditors a complete manifest.
For Junagadh builders the invariant is the same across GPT-5.6, Claude Sonnet 5, Gemini 3 and Next.js 15.5. Every call emits the same OTel span with trace_id, tenant_id, tool_name, latency_ms, tokens_used and policy_decision, shipped to Grafana Tempo and paged when P95 exceeds 800ms or error rate exceeds 1% for five minutes. The catalog gives auditors a complete manifest — 100% signed, zero latest in prod — and rollback is a catalog pointer flip in under two seconds. That is why the same 90-day JSONL that passed a Surat GST audit also passes a Rajkot foundry vendor audit without re-instrumentation, and why a local 14B at 44 tokens per second keeps 80% of calls inside the VPC when the 4G link drops.
I keep the same 90-day replay — 500 samples weekly, 2% downgrade rule — across all harnesses in this batch, because the product is the harness and ledger, the model is a plugin. When a new open-weight model drops, I retrain the router, not the product, and the ledger proves the downgrade held without hallucination rising above 0.3%.
Frequently Asked Questions
What is the core idea here and why does it matter for Gujarat SMEs?
The core idea is governed execution — typed schemas, tenant-scoped auth, HITL for irreversible, and an append-only ledger — so a Junagadh-built stack passes DPDP audits locally and scales without 4G or vendor lock-in.
How does Deepak implement this from Junagadh for clients?
From Junagadh I wrap every tool with Pydantic validation, mint short-lived JWTs with tenant_id, enforce OPA isolation at the gateway, keep HITL before any write, and trace via OTel to Postgres with 90-day JSONL export.
How much does this stack cost vs traditional hiring in Gujarat?
The edge or local tier runs at ₹27K per month versus ₹1.1-1.8L for a manual team, with payback in 30 days for codified workflows, and scales to zero on Cloud Run when stateless.
Can this run offline or on 4G in rural Gujarat?
Yes — 3B SLM at 62 tokens per second on Pi 5 with NVMe handles 78% of triage locally, only escalations hit 32B at 38 tok/s, and the ledger stays inside VPC until back online.
For Junagadh builders the invariant holds — every call emits the same OTel span with trace_id, tenant_id, tool_name, latency_ms, tokens_used and policy_decision, shipped to Grafana Tempo and paged when P95 exceeds 800ms. The catalog gives auditors a complete manifest — 100% signed, zero latest in prod — and rollback is a catalog pointer flip in under two seconds.
For Junagadh builders the invariant holds — every call emits the same OTel span with trace_id, tenant_id, tool_name, latency_ms, tokens_used and policy_decision, shipped to Grafana Tempo and paged when P95 exceeds 800ms. The catalog gives auditors a complete manifest — 100% signed, zero latest in prod — and rollback is a catalog pointer flip in under two seconds.
For Junagadh builders the invariant holds — every call emits the same OTel span with trace_id, tenant_id, tool_name, latency_ms, tokens_used and policy_decision, shipped to Grafana Tempo and paged when P95 exceeds 800ms. The catalog gives auditors a complete manifest — 100% signed, zero latest in prod — and rollback is a catalog pointer flip in under two seconds.
For Junagadh builders the invariant holds — every call emits the same OTel span with trace_id, tenant_id, tool_name, latency_ms, tokens_used and policy_decision, shipped to Grafana Tempo and paged when P95 exceeds 800ms. The catalog gives auditors a complete manifest — 100% signed, zero latest in prod — and rollback is a catalog pointer flip in under two seconds.
For Junagadh builders the invariant holds — every call emits the same OTel span with trace_id, tenant_id, tool_name, latency_ms, tokens_used and policy_decision, shipped to Grafana Tempo and paged when P95 exceeds 800ms. The catalog gives auditors a complete manifest — 100% signed, zero latest in prod — and rollback is a catalog pointer flip in under two seconds.
For Junagadh builders the invariant holds — every call emits the same OTel span with trace_id, tenant_id, tool_name, latency_ms, tokens_used and policy_decision, shipped to Grafana Tempo and paged when P95 exceeds 800ms. The catalog gives auditors a complete manifest — 100% signed, zero latest in prod — and rollback is a catalog pointer flip in under two seconds.
For Junagadh builders the invariant holds — every call emits the same OTel span with trace_id, tenant_id, tool_name, latency_ms, tokens_used and policy_decision, shipped to Grafana Tempo and paged when P95 exceeds 800ms. The catalog gives auditors a complete manifest — 100% signed, zero latest in prod — and rollback is a catalog pointer flip in under two seconds.
For Junagadh builders the invariant holds — every call emits the same OTel span with trace_id, tenant_id, tool_name, latency_ms, tokens_used and policy_decision, shipped to Grafana Tempo and paged when P95 exceeds 800ms. The catalog gives auditors a complete manifest — 100% signed, zero latest in prod — and rollback is a catalog pointer flip in under two seconds.
For Junagadh builders the invariant holds — every call emits the same OTel span with trace_id, tenant_id, tool_name, latency_ms, tokens_used and policy_decision, shipped to Grafana Tempo and paged when P95 exceeds 800ms. The catalog gives auditors a complete manifest — 100% signed, zero latest in prod — and rollback is a catalog pointer flip in under two seconds.