diff --git a/Cargo.toml b/Cargo.toml
index 08131b9..4282010 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "umya-spreadsheet"
-version = "2.1.1"
+version = "2.1.2"
 authors = ["MathNya <umya.net.info@gmail.com>"]
 repository = "https://github.com/MathNya/umya-spreadsheet"
 keywords = ["excel", "spreadsheet", "xlsx", "reader", "writer"]
diff --git a/README.md b/README.md
index d88cfb3..c8bb8b5 100644
--- a/README.md
+++ b/README.md
@@ -16,10 +16,17 @@
 Please mention in issues if you have any questions.
 
 ## Update details
-### ver 2.1.1
-* Minor bug fixes
-### ver 2.1.0
-* For image processing functions, you can select what you need.(Thank you. [xamgore](https://github.com/xamgore))
+### ver 2.1.2
+* cleanup() is now available.
+Remove invisible garbage data.
+Doing so may reduce file size.
+Processing may take some time.
+```rust
+let path = std::path::Path::new("./tests/test_files/aaa.xlsx");
+let mut book = umya_spreadsheet::reader::xlsx::read(path).unwrap();
+book.get_sheet_mut(&0).unwrap().cleanup();
+```
+
 * Minor bug fixes
 
 ## Usage
@@ -27,13 +34,13 @@ Please mention in issues if you have any questions.
 Add the following code to Cargo.toml
 ```toml
 [dependencies]
-umya-spreadsheet = "2.1.1"
+umya-spreadsheet = "2.1.2"
 
 # WebAssembly support
-umya-spreadsheet = { version = "2.1.1", features = ["js"] }
+umya-spreadsheet = { version = "2.1.2", features = ["js"] }
 
 # Use only png for image processing
-umya-spreadsheet = { version = "2.1.1", features = ["image/png"] }
+umya-spreadsheet = { version = "2.1.2", features = ["image/png"] }
 ```
 
 Add the following code to main.rs