diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0829ca6..6c7374a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,28 @@
+# v0.13.0 Feb 26th, 2026
+
+## Changelog
+
+### Features
+
+- Added comprehensive encoding and decoding functions for multiple formats:
+  - **Base64 Encoding/Decoding**: `encodeAsBase64()` and `decodeBase64()` with native fallbacks and ES5 polyfill support
+  - **URL-Safe Base64**: `encodeAsBase64Url()` and `decodeBase64Url()` for safe Base64 encoding in URLs (replaces `+` with `-`, `/` with `_`, removes padding)
+  - **Hexadecimal Encoding/Decoding**: `encodeAsHex()` and `decodeHex()` for hex string conversion
+  - **URI Encoding/Decoding**: `encodeAsUri()` and `decodeUri()` for URL component encoding
+  - All encoding functions include internal polyfills (`_encodeBase64Polyfill`, `_decodeBase64Polyfill`) for ES5 environment compatibility
+  - Consistent handling of null/undefined values across all encoding functions
+
+- Enhanced `createCustomError()` with `superArgsFn` parameter:
+  - New optional `superArgsFn` parameter allows custom transformation of constructor arguments before passing to base class
+  - Enables support for different argument orders and subsetting arguments passed to the base class constructor
+  - Useful for creating custom error subclasses with different constructor signatures than their base classes
+  - Example: HTTP error with `(statusCode, message)` signature can map to base `Error(message)` constructor
+
+### Performance Improvements
+
+- Improved performance of worker test execution
+  - Optimized test runner for faster execution in web worker environments
+
 # v0.12.6 Feb 2nd, 2026
 
 ## Changelog
diff --git a/README.md b/README.md
index b4af81f..8d7330d 100644
--- a/README.md
+++ b/README.md
@@ -31,7 +31,7 @@ npm install @nevware21/ts-utils --save
 
 **Recommended Version Specification:**
 ```json
-"@nevware21/ts-utils": ">= 0.12.6 < 2.x"
+"@nevware21/ts-utils": ">= 0.13.0 < 2.x"
 ```
 
 > Note: v0.x and v1.x maintain ES5 compatibility. Future v2.x releases will update the baseline to newer ECMAScript versions.
diff --git a/lib/package.json b/lib/package.json
index 830fc18..731a984 100644
--- a/lib/package.json
+++ b/lib/package.json
@@ -1,7 +1,7 @@
 {
     "name": "@nevware21/ts-utils",
     "description": "Comprehensive TypeScript/JavaScript utility library with cross-environment support (Node.js, browser, web worker) providing helper functions, polyfills (ES5-ES2023), type checking utilities, and optimized implementations for better minification and code readability",
-    "version": "0.12.6",
+    "version": "0.13.0",
     "homepage": "https://github.com/nevware21/ts-utils",
     "license": "MIT",
     "author": {
diff --git a/package.json b/package.json
index 435d42b..9e7b084 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
     "name": "@nevware21/ts-utils",
     "description": "Comprehensive TypeScript/JavaScript utility library with cross-environment support (Node.js, browser, web worker) providing helper functions, polyfills (ES5-ES2023), type checking utilities, and optimized implementations for better minification and code readability",
-    "version": "0.12.6",
+    "version": "0.13.0",
     "homepage": "https://github.com/nevware21/ts-utils",
     "license": "MIT",
     "author": {