diff --git a/error-codes.md b/error-codes.md
index f37697d88e27d..3dc2672c1eb1e 100644
--- a/error-codes.md
+++ b/error-codes.md
@@ -10,7 +10,7 @@ This document describes the problems encountered during the use of TiDB and prov
 
 ## Error codes
 
-TiDB is compatible with the error codes in MySQL, and in most cases returns the same error code as MySQL. For a list of error codes for MySQL, see [Server Error Message Reference](https://dev.mysql.com/doc/refman/5.7/en/server-error-reference.html). In addition, TiDB has the following unique error codes:
+TiDB is compatible with the error codes in MySQL, and in most cases returns the same error code as MySQL. For a list of error codes for MySQL, see [MySQL 5.7 Error Message Reference](https://dev.mysql.com/doc/mysql-errors/5.7/en/). In addition, TiDB has the following unique error codes:
 
 > **Note:**
 >
diff --git a/support.md b/support.md
index 391e4ad10cebb..674b6f66cf924 100644
--- a/support.md
+++ b/support.md
@@ -8,7 +8,7 @@ aliases: ['/docs/stable/support/','/docs/v4.0/support/','/docs/stable/support-re
 
 You can reach out to the community members via any one of the following ways:
 
-+ Slack Channel: [https://pingcap.com/tidbslack](https://pingcap.com/tidbslack)
++ Slack Channel: [https://slack.tidb.io/](https://slack.tidb.io/invite?team=tidb-community&channel=everyone&ref=pingcap)
 + Google Groups: [https://groups.google.com/forum/#!forum/tidb-user](https://groups.google.com/forum/#!forum/tidb-user)
 + Stack Overflow: [https://stackoverflow.com/questions/tagged/tidb](https://stackoverflow.com/questions/tagged/tidb)
 + Twitter: [https://twitter.com/PingCAP](https://twitter.com/PingCAP)