diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index b645649..819417f 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -7,7 +7,7 @@ Testkit is a Go module providing a modular builder framework to streamline test
 ## Working Effectively
 
 ### Bootstrap and Dependencies
-- Ensure Go 1.26.2+ is installed
+- Ensure Go 1.26.3+ is installed
 - Work from the repository root
 - `go mod tidy` -- downloads and organizes dependencies (takes ~2 seconds)
 - `go mod download` -- ensures all dependencies are available
@@ -151,7 +151,7 @@ pkg/test/       -- main library package (builder.go, examples.go, factory.go, do
 ```go
 module github.com/rios0rios0/testkit
 
-go 1.26.2
+go 1.26.3
 ```
 
 ### Example Application Output
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6979b17..d9b3b2e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,11 @@ Exceptions are acceptable depending on the circumstances (critical bug fixes tha
 
 ## [Unreleased]
 
+### Changed
+
+- changed the Go version to `1.26.3`
+- refreshed `.github/copilot-instructions.md` and `CLAUDE.md` to reflect the Go `1.26.3` version requirement
+
 ## [0.2.0] - 2026-04-28
 
 ### Added
diff --git a/CLAUDE.md b/CLAUDE.md
index 4a9023e..37142b4 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -4,7 +4,7 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 ## Project
 
-Go testing utility library (`github.com/rios0rios0/testkit`). Provides a modular builder framework for test environment setup. Pure library -- no deployable artifacts. Requires Go 1.26.2+.
+Go testing utility library (`github.com/rios0rios0/testkit`). Provides a modular builder framework for test environment setup. Pure library -- no deployable artifacts. Requires Go 1.26.3+.
 
 ## Commands
 
diff --git a/go.mod b/go.mod
index 3402c1f..3988975 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
 module github.com/rios0rios0/testkit
 
-go 1.26.2
+go 1.26.3