diff --git a/Cargo.toml b/Cargo.toml
index 8db625e..258479f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "fitting"
-version = "0.2.0"
+version = "0.2.1"
 authors = ["Masaharu TASHIRO <masatsr.kit@gmail.com>"]
 edition = "2018"
 
diff --git a/README.md b/README.md
index c1af93d..b1faab1 100644
--- a/README.md
+++ b/README.md
@@ -11,6 +11,11 @@ Curve fitting library for Rust
 
 ## Updates
 
+### 0.2.1
+
+- Error handing changed. Some functions returns Result instead of Option.
+- linalg.solve() is improved. Now it can solve NxM array with pivoting.
+
 ### 0.2.0
 
 - Using ndarray instead of nested Vec