translate feature descriptions for pingcap#4075 and #41163

releases/release-6.6.0.md

@@ -254,6 +254,20 @@ In v6.6.0-DMR, the key new features and improvements are as follows:
 
     For more information, see [documentation](/dm/dm-precheck.md#physical-import-check-items).
 
+* TiDB Lightning supports accessing Amazon S3 data via AWS IAM role keys and session tokens [#4075](https://github.com/pingcap/tidb/issues/40750) @[okJiang](https://github.com/okJiang) **tw@qiancai**
+
+    Before v6.6.0, TiDB Lightning only supports accessing S3 data via AWS IAM **user's access keys** (each access key consists of an access key ID and secret access key) so you cannot use a temporary session token to acess S3 data. Staring from v6.6.0, TiDB Lightning supports accessing S3 data via AWS IAM **role's access keys + session tokens** as well to improve the data security.
+
+    For more information, see [documentation](/tidb-lightning-data-source#import-data-from-amazon-s3).
+
+* TiDB Lightning supports enabling compressed transfers when sending key-value pairs to TiKV [#41163](https://github.com/pingcap/tidb/issues/41163) @[gozssky](https://github.com/gozssky) **tw@qiancai**
+
+    Starting from v6.6.0, TiDB Lightning supports compressing locally encoded and sorted key-value pairs for network transfer when sending them to TiKV, thus reducing the amount of data transferred over the network and lowering the network bandwidth overhead. In the earlier TiDB versions before this feature is supported, TiDB Lightning requires relatively high network bandwidth and incurs high traffic charges in case of large data volume.
+
+    This feature is disabled by default. To enable it, you can set the `compress-kv-pairs` configuration item of TiDB Lightning to "gzip" or "gz".
+
+    For more information, see [documentation](/tidb-lightning-configuration#tidb-lightning-task).
+
 ### TiDB data share subscription
 
 * The TiKV-CDC tool is now GA and supports subscribing to data changes of RawKV [#48](https://github.com/tikv/migration/issues/48) @[zeminzhou](https://github.com/zeminzhou) @[haojinming](https://github.com/haojinming) @[pingyu](https://github.com/pingyu) **tw@Oreoxmt**