diff --git a/.gitea/workflows/ci.yml b/.gitea/workflows/ci.yml
index 16103ce..53cb872 100644
--- a/.gitea/workflows/ci.yml
+++ b/.gitea/workflows/ci.yml
@@ -40,6 +40,20 @@ jobs:
             database: postgresql
             profile: --profile moodle45
             service: ci-moodle45
+          - moodle: "5.0.9"
+            moodle_id: moodle50
+            php: "8.2.33"
+            php_image: moodlehq/moodle-php-apache:8.2@sha256:3dae569f65e4ba1d2a413ea261d1dca72643bfa08a1e28a3d104a4024c4f040c
+            database: postgresql
+            profile: --profile moodle50
+            service: ci-moodle50
+          - moodle: "5.1.6"
+            moodle_id: moodle51
+            php: "8.2.33"
+            php_image: moodlehq/moodle-php-apache:8.2@sha256:3dae569f65e4ba1d2a413ea261d1dca72643bfa08a1e28a3d104a4024c4f040c
+            database: postgresql
+            profile: --profile moodle51
+            service: ci-moodle51
     env:
       COMPOSE_PROJECT_NAME: local_webhooks_${{ gitea.run_id }}_${{ gitea.run_attempt }}_${{ matrix.moodle_id }}_${{ matrix.database }}
     steps:
diff --git a/README.md b/README.md
index fcda76a..e7d92aa 100644
--- a/README.md
+++ b/README.md
@@ -10,11 +10,13 @@ The `develop` branch is unreleased modernization work toward `6.0.0` and is not
 
 ## Current CI baseline
 
-Gitea Actions currently runs three blocking compatibility checks:
+Gitea Actions currently runs five blocking compatibility checks:
 
 - Moodle `5.2.2` on PHP `8.4` with PostgreSQL `16`;
 - Moodle `5.2.2` on PHP `8.4` with MySQL `8.4`;
-- Moodle `4.5.13` LTS on PHP `8.1.34` with PostgreSQL `16`.
+- Moodle `4.5.13` LTS on PHP `8.1.34` with PostgreSQL `16`;
+- Moodle `5.0.9` on PHP `8.2.33` with PostgreSQL `16`;
+- Moodle `5.1.6` on PHP `8.2.33` with PostgreSQL `16`.
 
 This is an incremental development baseline, not the final support matrix.
 
@@ -47,6 +49,24 @@ docker compose --profile moodle45 up --abort-on-container-exit --exit-code-from
 docker compose --profile moodle45 down --volumes --remove-orphans --rmi local
 ```
 
+Moodle 5.0 with PostgreSQL:
+
+```bash
+export COMPOSE_PROJECT_NAME=local_webhooks_local_moodle50_postgresql
+docker compose --profile moodle50 build --pull ci-moodle50
+docker compose --profile moodle50 up --abort-on-container-exit --exit-code-from ci-moodle50 ci-moodle50
+docker compose --profile moodle50 down --volumes --remove-orphans --rmi local
+```
+
+Moodle 5.1 with PostgreSQL:
+
+```bash
+export COMPOSE_PROJECT_NAME=local_webhooks_local_moodle51_postgresql
+docker compose --profile moodle51 build --pull ci-moodle51
+docker compose --profile moodle51 up --abort-on-container-exit --exit-code-from ci-moodle51 ci-moodle51
+docker compose --profile moodle51 down --volumes --remove-orphans --rmi local
+```
+
 ## License
 
 [GNU GPLv3](LICENSE.txt). Copyright (c) [Valentin Popov](mailto:info@valentineus.link).
diff --git a/compose.yaml b/compose.yaml
index f1c6dff..9303a52 100644
--- a/compose.yaml
+++ b/compose.yaml
@@ -13,6 +13,11 @@ x-ci: &ci
       moodle-plugin-ci --version
       moodle-plugin-ci install --plugin /plugin --branch "$$MOODLE_BRANCH" --db-host "$$DB_HOST"
       test "$$(git -C /workspace/moodle rev-parse HEAD)" = "$$MOODLE_COMMIT"
+      moodle_root=/workspace/moodle
+      moodle_wwwroot="$$moodle_root/$$MOODLE_WWWROOT"
+      test -f "$$moodle_wwwroot/version.php"
+      test -d "$$moodle_wwwroot/local/webhooks"
+      test "$$MOODLE_WWWROOT" != public || test ! -e "$$moodle_root/version.php"
       moodle-plugin-ci phplint
       moodle-plugin-ci phpcs --max-warnings 0
       moodle-plugin-ci phpdoc --max-warnings 0
@@ -59,6 +64,7 @@ services:
       DB_USER: postgres
       MOODLE_BRANCH: v5.2.2
       MOODLE_COMMIT: acfa383c13dd46c83ca82894a8e95fac273fda33
+      MOODLE_WWWROOT: public
       NPM_CONFIG_FETCH_RETRIES: 5
 
   ci-mysql:
@@ -75,6 +81,7 @@ services:
       DB_USER: root
       MOODLE_BRANCH: v5.2.2
       MOODLE_COMMIT: acfa383c13dd46c83ca82894a8e95fac273fda33
+      MOODLE_WWWROOT: public
       NPM_CONFIG_FETCH_RETRIES: 5
 
   ci-moodle45:
@@ -95,4 +102,47 @@ services:
       DB_USER: postgres
       MOODLE_BRANCH: v4.5.13
       MOODLE_COMMIT: 8cbae18a2898cfd8266ec91ac206e12004f0ff5f
+      MOODLE_WWWROOT: .
+      NPM_CONFIG_FETCH_RETRIES: 5
+
+  ci-moodle50:
+    <<: *ci
+    profiles:
+      - moodle50
+    build:
+      context: .
+      dockerfile: .docker/ci/Dockerfile
+      args:
+        PHP_IMAGE: moodlehq/moodle-php-apache:8.2@sha256:3dae569f65e4ba1d2a413ea261d1dca72643bfa08a1e28a3d104a4024c4f040c
+    depends_on:
+      postgres:
+        condition: service_healthy
+    environment:
+      DB: pgsql
+      DB_HOST: postgres
+      DB_USER: postgres
+      MOODLE_BRANCH: v5.0.9
+      MOODLE_COMMIT: 152bf2ebbdd1f994331af21c80332b8d9051581c
+      MOODLE_WWWROOT: .
+      NPM_CONFIG_FETCH_RETRIES: 5
+
+  ci-moodle51:
+    <<: *ci
+    profiles:
+      - moodle51
+    build:
+      context: .
+      dockerfile: .docker/ci/Dockerfile
+      args:
+        PHP_IMAGE: moodlehq/moodle-php-apache:8.2@sha256:3dae569f65e4ba1d2a413ea261d1dca72643bfa08a1e28a3d104a4024c4f040c
+    depends_on:
+      postgres:
+        condition: service_healthy
+    environment:
+      DB: pgsql
+      DB_HOST: postgres
+      DB_USER: postgres
+      MOODLE_BRANCH: v5.1.6
+      MOODLE_COMMIT: 17513f6614237b530de7903fe32117fa026384c2
+      MOODLE_WWWROOT: public
       NPM_CONFIG_FETCH_RETRIES: 5