diff --git a/manual/upgrade/seafile_obsolete_configurations.md b/manual/upgrade/seafile_obsolete_configurations.md
new file mode 100644
index 00000000..59d9acd7
--- /dev/null
+++ b/manual/upgrade/seafile_obsolete_configurations.md
@@ -0,0 +1,54 @@
+# Seafile Obsolete Configurations
+
+The Seafile configuration files are located in the `/opt/seafile-data/seafile/conf/` directory.
+
+## Seafile 12 to 13 Obsolete Configurations
+
+### seafevents.conf
+
+You should remove the `[DATABASE]` configuration block.
+
+### seafile.conf
+You should remove the `[database]` and `[memcached]` configuration block.
+
+### seahub_settings.py
+You should remove the `SERVICE_URL`, `DATABASES = {...}`, `CACHES = {...}`, `COMPRESS_CACHE_BACKEND` and `FILE_SERVER_ROOT` configuration block.
+
+### env
+The following configurations are removed or renamed to new ones.
+
+```shell
+SEAFILE_MEMCACHED_IMAGE=docker.seafile.top/seafileltd/memcached:1.6.29
+
+INIT_S3_STORAGE_BACKEND_CONFIG=false
+INIT_S3_COMMIT_BUCKET=<your-commit-objects>
+INIT_S3_FS_BUCKET=<your-fs-objects>
+INIT_S3_BLOCK_BUCKET=<your-block-objects>
+INIT_S3_KEY_ID=<your-key-id>
+INIT_S3_SECRET_KEY=<your-secret-key>
+INIT_S3_USE_V4_SIGNATURE=true
+INIT_S3_AWS_REGION=us-east-1
+INIT_S3_HOST=
+INIT_S3_USE_HTTPS=true
+
+NOTIFICATION_SERVER_VOLUME=/opt/notification-data
+
+SS_S3_USE_V4_SIGNATURE=false
+SS_S3_ACCESS_ID=<your access id>
+SS_S3_ACCESS_SECRET=<your access secret>
+SS_S3_ENDPOINT=
+SS_S3_BUCKET=<your bucket name>
+SS_S3_USE_HTTPS=true
+SS_S3_PATH_STYLE_REQUEST=true
+SS_S3_AWS_REGION=us-east-1
+SS_S3_SSE_C_KEY=<your SSE-C key>
+```
+
+## Seafile 11 to 12 Obsolete Configurations
+
+### ccnet.conf
+You should remove the entire `ccnet.conf` configuration file.
+
+### seafile.conf
+
+You should remove the `[notification]` configuration block.
diff --git a/mkdocs.yml b/mkdocs.yml
index 3daa2699..d63dbc20 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -198,6 +198,7 @@ nav:
     - Upgrade notes for 11.0.x: upgrade/upgrade_notes_for_11.0.x.md
     - Upgrade notes for 10.0.x: upgrade/upgrade_notes_for_10.0.x.md
     - Upgrade notes for 9.0.x: upgrade/upgrade_notes_for_9.0.x.md
+    - Summary of obsolete configurations: upgrade/seafile_obsolete_configurations.md
   - Developing:
     - Outline: develop/README.md
     - How to Build Seafile: