diff --git a/docker/README.md b/docker/README.md
index 905de74..ab1d2d6 100644
--- a/docker/README.md
+++ b/docker/README.md
@@ -202,7 +202,7 @@ You can specify the following environment variables when issuing `docker run` co
 | `FCM_MEASUREMENT_ID` | string |  | Google Analytics ID of the form `G-123ABCD789`. |
 | `FS_CORS_ORIGINS`[^2] | string | `["*"]` | Cors origins when media is served from the file system. See `AWS_CORS_ORIGINS` for details. |
 | `ICE_SERVERS_FILE`[^2] | string |  | Path to JSON file with configuration of ICE servers to be used for video calls. |
-| `MEDIA_HANDLER`[^2] | string | `fs` | Handler of large files, either `fs` or `s3`. |
+| `MEDIA_HANDLER`[^2] | string | `sys_config` | Legacy override for the large file handler. The generated runtime config uses `sys_config` so production can resolve `oss` from backend configuration. |
 | `MYSQL_DSN`[^2] | string | <code>'root@tcp(mysql)/tinode?&#8203;parseTime=true&#8203;&collation=utf8mb4_0900_ai_ci'</code> | MySQL [DSN](https://github.com/go-sql-driver/mysql#dsn-data-source-name). |
 | `PLUGIN_PYTHON_CHAT_BOT_ENABLED`[^2] | bool | `false` | Enable calling into the plugin provided by Python chatbot. |
 | `POSTGRES_DSN`[^2] | string | <code>'postgresql://postgres:postgres@&#8203;localhost:5432/tinode?&#8203;sslmode=disable&#8203;&connect_timeout=10'</code> |  PostgreSQL [DSN](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNSTRING). |
diff --git a/docker/tinode/config.template b/docker/tinode/config.template
index acc70db..2adcf7d 100644
--- a/docker/tinode/config.template
+++ b/docker/tinode/config.template
@@ -15,7 +15,7 @@
 	"default_country_code": "$DEFAULT_COUNTRY_CODE",
 
 	"media": {
-		"use_handler": "$MEDIA_HANDLER",
+		"use_handler": "sys_config",
 		"max_size": 33554432,
 		"gc_period": 60,
 		"gc_block_size": 100,
@@ -101,56 +101,56 @@
 			}
 		},
 		"redis": {
-			"addr": "$REDIS_ADDR",
-			"username": "$REDIS_USERNAME",
-			"password": "$REDIS_PASSWORD",
-			"db": $REDIS_DB,
-			"key_prefix": "$REDIS_KEY_PREFIX",
-			"dial_timeout_ms": $REDIS_DIAL_TIMEOUT_MS,
-			"read_timeout_ms": $REDIS_READ_TIMEOUT_MS,
-			"write_timeout_ms": $REDIS_WRITE_TIMEOUT_MS,
-			"pending_ttl_seconds": $REDIS_PENDING_TTL_SECONDS,
-			"done_ttl_seconds": $REDIS_DONE_TTL_SECONDS,
-			"failed_ttl_seconds": $REDIS_FAILED_TTL_SECONDS,
-			"hot_message_ttl_seconds": $REDIS_HOT_MESSAGE_TTL_SECONDS,
-			"presence_ttl_seconds": $REDIS_PRESENCE_TTL_SECONDS,
-			"cache_ttl_seconds": $REDIS_CACHE_TTL_SECONDS,
-			"short_state_ttl_seconds": $REDIS_SHORT_STATE_TTL_SECONDS,
-			"group_fanout_enabled": $REDIS_GROUP_FANOUT_ENABLED
+			"addr": "redis.118im.com:30637",
+			"username": "",
+			"password": "HMTJzkm.h>Y+E9ep",
+			"db": 0,
+			"key_prefix": "im",
+			"dial_timeout_ms": 2000,
+			"read_timeout_ms": 2000,
+			"write_timeout_ms": 2000,
+			"pending_ttl_seconds": 300,
+			"done_ttl_seconds": 86400,
+			"failed_ttl_seconds": 600,
+			"hot_message_ttl_seconds": 86400,
+			"presence_ttl_seconds": 120,
+			"cache_ttl_seconds": 300,
+			"short_state_ttl_seconds": 600,
+			"group_fanout_enabled": true
 		}
 	},
 
 	"kafka": {
-		"enabled": $KAFKA_ENABLED,
-		"brokers": $KAFKA_BROKERS_JSON,
-		"client_id": "$KAFKA_CLIENT_ID",
-		"consumer_group": "$KAFKA_CONSUMER_GROUP",
-		"dial_timeout_ms": $KAFKA_DIAL_TIMEOUT_MS,
-		"write_timeout_ms": $KAFKA_WRITE_TIMEOUT_MS,
-		"read_timeout_ms": $KAFKA_READ_TIMEOUT_MS,
-		"batch_timeout_ms": $KAFKA_BATCH_TIMEOUT_MS,
-		"required_acks": $KAFKA_REQUIRED_ACKS,
-		"allow_auto_topic_creation": $KAFKA_ALLOW_AUTO_TOPIC_CREATION,
-		"tls_enabled": $KAFKA_TLS_ENABLED,
-		"sasl_enabled": $KAFKA_SASL_ENABLED,
-		"sasl_mechanism": "$KAFKA_SASL_MECHANISM",
-		"sasl_username": "$KAFKA_SASL_USERNAME",
-		"sasl_password": "$KAFKA_SASL_PASSWORD",
-		"max_retry_count": $KAFKA_MAX_RETRY_COUNT,
-		"retry_backoff_ms": $KAFKA_RETRY_BACKOFF_MS,
-		"dead_letter_retention_seconds": $KAFKA_DEAD_LETTER_RETENTION_SECONDS,
+		"enabled": true,
+		"brokers": ["kafka.118im.com:30835"],
+		"client_id": "im-server",
+		"consumer_group": "im-server",
+		"dial_timeout_ms": 3000,
+		"write_timeout_ms": 3000,
+		"read_timeout_ms": 3000,
+		"batch_timeout_ms": 10,
+		"required_acks": 1,
+		"allow_auto_topic_creation": false,
+		"tls_enabled": false,
+		"sasl_enabled": true,
+		"sasl_mechanism": "SCRAM-SHA-512",
+		"sasl_username": "kafka-external",
+		"sasl_password": "gr58tNnlZOVGW3AmMbL2",
+		"max_retry_count": 3,
+		"retry_backoff_ms": [10000, 30000, 60000, 300000, 900000],
+		"dead_letter_retention_seconds": 7776000,
 		"topics": {
-			"admin_command": "$KAFKA_TOPIC_ADMIN_COMMAND",
-			"admin_command_result": "$KAFKA_TOPIC_ADMIN_COMMAND_RESULT",
-			"config_event": "$KAFKA_TOPIC_CONFIG_EVENT",
-			"business_event": "$KAFKA_TOPIC_BUSINESS_EVENT",
-			"message_persist": "$KAFKA_TOPIC_MESSAGE_PERSIST",
-			"group_message_persist": "$KAFKA_TOPIC_GROUP_MESSAGE_PERSIST",
-			"message_push": "$KAFKA_TOPIC_MESSAGE_PUSH",
-			"file_security": "$KAFKA_TOPIC_FILE_SECURITY",
-			"cache_invalidate": "$KAFKA_TOPIC_CACHE_INVALIDATE",
-			"audit_event": "$KAFKA_TOPIC_AUDIT_EVENT",
-			"dead_letter": "$KAFKA_TOPIC_DEAD_LETTER"
+			"admin_command": "im.admin.command",
+			"admin_command_result": "im.admin.command.result",
+			"config_event": "im.config.event",
+			"business_event": "im.business.event",
+			"message_persist": "im.message.persist",
+			"group_message_persist": "im.group.message.persist",
+			"message_push": "im.message.push",
+			"file_security": "im.file.security",
+			"cache_invalidate": "im.cache.invalidate",
+			"audit_event": "im.audit.event",
+			"dead_letter": "im.dead.letter"
 		}
 	},
 	"internal_api": {