tiflash: Update tiflash upgrade guide (#21619) (#21625)

Author: ti-chi-bot

tiflash-upgrade-guide.md

@@ -82,7 +82,7 @@ If you do not enable [dynamic pruning mode](/partitioned-table.md#dynamic-prunin
 
 ## From v5.x or v6.0 to v6.2
 
-In TiDB v6.2, TiFlash upgrades its data storage format to the V3 version. Therefore, when you upgrade TiFlash from v5.x or v6.0 to v6.2, besides functional changes in [TiFlash Proxy](#tiflash-proxy) and [Dynamic pruning](#dynamic-pruning), you also need to pay attention to the functional change in PageStorage.
+In TiDB v6.2, TiFlash upgrades its data storage format to V3 to reduce write amplification and improve TiFlash stability. When you upgrade from v5.x, v6.0, or v6.1 to v6.2 or a later version, in addition to the functional changes in [TiFlash Proxy](#tiflash-proxy) and [Dynamic pruning](#dynamic-pruning), you also need to pay attention to the functional change in PageStorage.
 
 ### PageStorage
 
@@ -105,14 +105,25 @@ You can check whether tables still use the old data format on Grafana: **TiFlash
 - Only V3: Number of tables using PageStorage V3 (including partitions)
 - Mix Mode: Number of tables with data format converted from PageStorage V2 to PageStorage V3 (including partitions)
 
+> **Note:**
+>
+> The following patch versions have a known issue (Issue [#9039](https://github.com/pingcap/tiflash/issues/9039)). Upgrading to these versions might cause TiFlash data corruption.
+> 
+> - v6.5.0 to v6.5.9
+> - v6.6.0
+> - v7.0.0
+> - v7.1.0 to v7.1.5
+> - v7.2.0
+> - v7.3.0
+> - v7.4.0
+> - v7.5.0 to v7.5.1
+> 
+> It is recommended that you upgrade to v6.5.10, v7.1.6, v7.5.2, or a later version where this issue has been fixed.
+
 **Workaround for downgrading TiFlash in testing or other special scenarios**
 
 You can forcibly scale in the target TiFlash node and then replicate data from TiKV again. For detailed steps, see [Scale in a TiFlash cluster](/scale-tidb-using-tiup.md#scale-in-a-tiflash-cluster).
 
-## From v6.1 to v6.2
-
-When you upgrade TiFlash from v6.1 to v6.2, pay attention to the change in data storage format. For details, see [PageStorage](#pagestorage).
-
 ## From v6.x or v7.x to v7.3 with `storage.format_version = 5` configured
 
 Starting from v7.3, TiFlash introduces a new DTFile version: DTFile V3 (experimental). This new DTFile version can merge multiple small files into a single larger file to reduce the total number of files. In v7.3, the default DTFile version is still V2. To use V3, you can set the [TiFlash configuration parameter](/tiflash/tiflash-configuration.md) `storage.format_version = 5`. After the setting, TiFlash can still read V2 DTFiles and will gradually rewrite existing V2 DTFiles to V3 DTFiles during subsequent data compaction.