diff --git a/CHANGELOG.md b/CHANGELOG.md
index b263b4f..9c456b5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -37,9 +37,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   8.1 handles FrankenPHP worker mode natively via its built-in
   `FrankenPhpWorkerRunner`. The `extra.runtime` override in
   `composer.json` was removed so the runtime auto-detects FrankenPHP.
-  Note: the old package's `FRANKENPHP_LOOP_MAX` env var (default 500
-  requests per worker) is no longer read; worker lifecycle is now managed
-  by FrankenPHP itself.
+  The old package's `FRANKENPHP_LOOP_MAX` env var is no longer read;
+  an equivalent recycle limit is restored via the new `MAX_REQUESTS`
+  setting below.
+
+### Added
+- **`MAX_REQUESTS` worker-thread recycle limit** — The `Caddyfile` now
+  sets FrankenPHP's native `max_requests` from the `MAX_REQUESTS`
+  environment variable: each PHP worker thread is gracefully restarted
+  after N requests while others keep serving, containing slow memory
+  growth across long uptime. The image default is **500** (matching the
+  previous `runtime/frankenphp-symfony` default), baked in as a Docker
+  build arg and overridable at runtime (`MAX_REQUESTS=0` disables
+  restarts). Arbitrary `frankenphp`-block configuration is still
+  possible via the stock `FRANKENPHP_CONFIG` env var.
 
 ## [1.0.0] — v1.0 Release
 
diff --git a/Caddyfile b/Caddyfile
index dd48371..8ba514d 100644
--- a/Caddyfile
+++ b/Caddyfile
@@ -1,3 +1,17 @@
+{
+	frankenphp {
+		# Restart each PHP worker thread after this many requests, containing
+		# slow memory growth across long uptime. Preserves the 7.4-era default
+		# loop count of runtime/frankenphp-symfony (500) after the Symfony 8.1
+		# upgrade. Set MAX_REQUESTS=0 to disable restarts. The Dockerfile bakes
+		# in the default of 500 via build arg; override at runtime with:
+		#   docker run -e MAX_REQUESTS=5000 ...
+		# For full control, the stock FRANKENPHP_CONFIG env var can inject any
+		# directive under this block instead.
+		max_requests {$MAX_REQUESTS}
+	}
+}
+
 http://
 root public/
 rewrite index.php
diff --git a/Dockerfile b/Dockerfile
index b83dbf3..b52b9ad 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -45,6 +45,15 @@ ENV APP_DEBUG=0
 ENV APP_ENV=prod
 ENV APP_SHARE_DIR=/data/preauth
 
+# worker thread lifecycle: restart each PHP thread after N requests to
+# contain slow memory growth. Matches the previous default loop count of
+# runtime/frankenphp-symfony (removed in the Symfony 8.1 upgrade).
+# Expose as a build arg so images can bake in a different default;
+# MAX_REQUESTS=0 disables restarts. Runtime override: the same env var is
+# read by the Caddyfile placeholder.
+ARG MAX_REQUESTS=500
+ENV MAX_REQUESTS=$MAX_REQUESTS
+
 # load application into final image
 WORKDIR /app
 COPY --from=build /data/preauth /data/preauth
diff --git a/docs/example.env b/docs/example.env
index 96da772..34d7459 100644
--- a/docs/example.env
+++ b/docs/example.env
@@ -24,6 +24,14 @@
 # once blocked, do we respond with "I'm a teapot", false to use "Too many requests"
 #TEAPOT=true                # default enabled, boolean
 
+# --- server / worker options ---
+
+# (container/deployment only) restart each FrankenPHP worker thread after
+# this many requests, containing memory growth across long uptime;
+# matching the default from the old runtime/frankenphp-symfony package.
+# 0 disables restarts. consumed by the Caddyfile, not the PHP app.
+#MAX_REQUESTS=500           # default 500
+
 # --- remote-user header ---
 # Controls the value sent in the Remote-User header on successful auth.
 # session: the session id (default, backward-compatible)
diff --git a/docs/symfony-8.1-upgrade-plan.md b/docs/symfony-8.1-upgrade-plan.md
index d7cdc81..e625716 100644
--- a/docs/symfony-8.1-upgrade-plan.md
+++ b/docs/symfony-8.1-upgrade-plan.md
@@ -1,12 +1,29 @@
 # Upgrade Plan: Symfony 7.4 → 8.1
 
-**Status:** Planning
+**Status:** ✅ Implemented on branch `feat/symfony-8.1-upgrade-plan`
+(Phases 0–3 & state audit complete; Phases 4–5 = staging + release)
 **Target:** Symfony `8.1.*` (all symfony components)
-**Current:** Symfony `7.4.*`
+**Was:** Symfony `7.4.*` → **resolved 8.1.2–8.1.6**
 **Prepared:** 2026-09-07
 
 ---
 
+## Implementation results
+
+| Phase | Result |
+|-------|--------|
+| 0 Deprecation sweep | ✅ Clean — suite runs with `failOnDeprecation=true`, zero hits on 7.4; the 8.x jump needed **no app code changes**. |
+| 1 Composer bump | ✅ `runtime/frankenphp-symfony` removed, `extra.runtime` deleted, all `symfony/*` at `8.1.*` (framework-bundle 8.1.6, twig-bundle 8.1.2); ride-alongs PHPUnit 13.3.2, Twig 3.28, otphp 11.5. Boots on **v8.1.6**. |
+| 2 Config refresh | ✅ `config/reference.php` is gitignored, auto-regenerated by Flex. Prod `cache:clear`+`cache:warmup`, `lint:container`/`lint:yaml`/`lint:twig` all pass. |
+| 3 Tests | ✅ **295 tests / 612 assertions green** on 8.1; php-cs-fixer 0 fixable files. |
+| State audit | ✅ All `src/` services are `final readonly` with ctor-injected deps — no mutable state, kernel reuse under `FrankenPhpWorkerRunner` is safe. |
+| Loop-max parity | ✅ `Caddyfile` sets `max_requests {$MAX_REQUESTS}`; default **500** baked into the image via Docker build arg (matches old package default), runtime-overridable. See §2 note. |
+
+Phases 4–5 (staging smoke + release) are pending — everything else in
+this document describes what was planned **and is now done**.
+
+---
+
 ## 1. Why we can leapfrog 8.0
 
 Symfony 7.4 and 8.0 were released simultaneously (Nov 2025) and are
@@ -191,7 +208,7 @@ twig-bundle, uid, yaml) and tick each item against this codebase.
 | 1 | **composer bump**: branch `feat/symfony-8.1`; edit composer.json per §3–§4; `composer remove runtime/frankenphp-symfony`; `composer update`; re-sync recipes. | Installs clean on PHP 8.5; `bin/console about` shows 8.1.x. |
 | 2 | **Config refresh**: regenerate `config/reference.php`; review framework/twig/rate-limiter defaults; commit config changes. | `cache:clear` + warmup pass in dev & prod envs. |
 | 3 | **Tests**: full phpunit suite + php-cs-fixer; fix failures (expected: minor — event/type related). | Suite green in CI. |
-| 4 | **Staging smoke**: build image, run under FrankenPHP worker mode; verify TOTP login flow, backup codes, rate limiting (burst + teapot mode), public paths, central-auth subdomain flow; watch memory across >500 requests (old loop_max default no longer applies — see §2 note). | No state leaks across worker requests; healthcheck passes. |
+| 4 | **Staging smoke**: build image, run under FrankenPHP worker mode; verify TOTP login flow, backup codes, rate limiting (burst + teapot mode), public paths, central-auth subdomain flow; watch memory across >500 requests to confirm threads recycle via the Caddyfile `max_requests` setting (see §2 note). | No state leaks across worker requests; worker threads recycle at the configured request count; healthcheck passes. |
 | 5 | **Docs + release**: update readme/DESIGN_CONSIDERATIONS ("symfony 8.1, built-in FrankenPHP runtime"); tag a minor release per CHANGELOG conventions. | Release published; image rebuilt & pushed. |
 
 **Rollback:** the upgrade is a single composer.lock + config diff.
diff --git a/readme.md b/readme.md
index 1127023..58fa532 100644
--- a/readme.md
+++ b/readme.md
@@ -113,6 +113,7 @@ for the complete reference.
 |----------|---------|-------------|
 | `IP_TTL` | `0` | Seconds to allow all traffic from an IP after login (0 = disabled). |
 | `TEAPOT` | `1` | Respond with 418 instead of 429 when rate-limited (boolean). |
+| `MAX_REQUESTS` | `500` | Restart each FrankenPHP worker thread after this many requests to contain memory growth (`0` = unlimited). Maps to the Caddyfile `max_requests` directive. |
 
 ### Remote-User Header