diff --git a/docs/sql-migration-guide.md b/docs/sql-migration-guide.md
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@@ -64,6 +64,7 @@ license: |
 ## Upgrading from Spark SQL 3.5.1 to 3.5.2
 
 - Since 3.5.2, MySQL JDBC datasource will read TINYINT UNSIGNED as ShortType, while in 3.5.1, it was wrongly read as ByteType.
+- Since 3.5.2, the `base64` function will return a non-chunked string. To restore the behavior of chunking base64 encoded strings into lines of at most 76 characters, set `spark.sql.legacy.chunkBase64String.enabled` to `true`.
 
 ## Upgrading from Spark SQL 3.5.0 to 3.5.1