Fix 404 links (#7767)

docs/en/concepts-and-designs/manual-sdk.md

@@ -7,4 +7,4 @@ Our incredible community has contributed to the manual instrument SDK.
 See these protocols in [protocols document](../protocols/README.md).
 
 ## Envoy tracer
-Envoy has its internal tracer implementation for SkyWalking. Read [SkyWalking Tracer doc](https://www.envoyproxy.io/docs/envoy/latest/api-v3/config/trace/v3/skywalking.proto.html?highlight=skywalking) and [SkyWalking tracing sandbox](https://www.envoyproxy.io/docs/envoy/latest/start/sandboxes/skywalking_tracing.html?highlight=skywalking) for more details.
+Envoy has its internal tracer implementation for SkyWalking. Read [SkyWalking Tracer doc](https://www.envoyproxy.io/docs/envoy/v1.19.1/api-v3/config/trace/v3/skywalking.proto.html?highlight=skywalking) and [SkyWalking tracing sandbox](https://www.envoyproxy.io/docs/envoy/v1.19.1/start/sandboxes/skywalking_tracing?highlight=skywalking) for more details.

docs/en/setup/envoy/examples/metrics/README.md

 # Sending Envoy Metrics to SkyWalking OAP Server Example
 
-This is an example of sending [Envoy Stats](https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/observability/statistics#arch-overview-statistics) to SkyWalking OAP server
-through [Metric Service](https://www.envoyproxy.io/docs/envoy/v1.18.2/api-v2/config/metrics/v2/metrics_service.proto).
+This is an example of sending [Envoy Stats](https://www.envoyproxy.io/docs/envoy/v1.19.1/intro/arch_overview/observability/statistics) to SkyWalking OAP server
+through Metric Service [v2](https://www.envoyproxy.io/docs/envoy/v1.18.2/api-v2/config/metrics/v2/metrics_service.proto) and [v3](https://www.envoyproxy.io/docs/envoy/v1.19.1/api-v3/config/metrics/v3/metrics_service.proto).
 
 ## Running the example