diff --git a/.github/workflows/lint.yaml b/.github/workflows/lint.yaml
index 5d73696..855b9d9 100644
--- a/.github/workflows/lint.yaml
+++ b/.github/workflows/lint.yaml
@@ -24,5 +24,5 @@ jobs:
       - name: Golangci lint
         uses: golangci/golangci-lint-action@v9
         with:
-          version: v2.7.1
+          version: v2.15.0
           install-mode: goinstall
diff --git a/.golangci.yaml b/.golangci.yaml
index 0aeff3a..fbaf3a7 100644
--- a/.golangci.yaml
+++ b/.golangci.yaml
@@ -21,6 +21,7 @@ linters:
     - govet
     - ineffassign
     - misspell
+    - modernize
     - nakedret
     - reassign
     - revive
@@ -111,6 +112,7 @@ linters:
           - dupl
           - errcheck
           - funlen
+          - goconst
           - gocyclo
           - gosec
         path: _test\.go
diff --git a/AGENTS.md b/AGENTS.md
index a8b499c..91e8ad6 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -27,7 +27,7 @@ This guide helps agentic coding agents work effectively with the chartify codeba
 ### Linting and Formatting
 - **Format code**: `go fmt ./...`
 - **Vet code**: `go vet ./...` (42s, set timeout 120s+)
-- **NOTE**: golangci-lint config (.golangci.yaml) has compatibility issues with recent versions. Use `go fmt` and `go vet` for validation.
+- **Lint**: `golangci-lint run` (uses .golangci.yaml; CI runs v2.15.0). If local golangci-lint fails with "export data version" errors, reinstall it with the same Go toolchain as go.mod: `GOTOOLCHAIN=go1.27.2 go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.15.0`
 
 ### Running the CLI
 - Basic usage: `./chartify -o OUTPUT_DIR RELEASE_NAME CHART_OR_MANIFEST_PATH`
@@ -122,11 +122,12 @@ Run these commands to ensure CI passes:
 ```bash
 go fmt ./...
 go vet ./...
+golangci-lint run
 CGO_ENABLED=0 go test ./...
 ```
 
 ### Prerequisites
-- Go 1.26.0+
+- Go 1.27.2+
 - Helm v4.3.1 (helm command)
 - Kustomize v5.8.0+ (kustomize command)
 
diff --git a/README.md b/README.md
index 755ede5..d5e859f 100644
--- a/README.md
+++ b/README.md
@@ -36,7 +36,7 @@ go build -o chartreposerver ./cmd/chartreposerver
 
 ### Prerequisites
 
-- Go 1.26.0+
+- Go 1.27.2+
 - Helm v4.3.1 (helm command)
 - Kustomize v5.8.0+ (kustomize command, optional, for kustomize integration)
 
diff --git a/chartify.go b/chartify.go
index c310bb3..3726a33 100644
--- a/chartify.go
+++ b/chartify.go
@@ -135,7 +135,7 @@ type ChartifyOpts struct {
 	// TemplateFuncs is the FuncMap used while rendering .gotmpl files in the target directory
 	TemplateFuncs template.FuncMap
 	// TemplateData is the data available via {{ . }} within .gotmpl files
-	TemplateData interface{}
+	TemplateData any
 
 	// TemplateArgs to pass Flags to helm template
 	TemplateArgs string
diff --git a/chartify_test.go b/chartify_test.go
index f69abed..6d92c2a 100644
--- a/chartify_test.go
+++ b/chartify_test.go
@@ -179,7 +179,7 @@ func TestDepCommandSelection(t *testing.T) {
 			ReadDir:   os.ReadDir,
 			Walk:      filepath.Walk,
 			Exists:    exists,
-			Logf:      func(string, ...interface{}) {},
+			Logf:      func(string, ...any) {},
 			MakeTempDir: func(release, chart string, opts *ChartifyOpts) string {
 				return ""
 			},
diff --git a/command.go b/command.go
index dc95fef..45a8435 100644
--- a/command.go
+++ b/command.go
@@ -2,6 +2,7 @@ package chartify
 
 import (
 	"io"
+	"maps"
 	"os"
 	"os/exec"
 	"strings"
@@ -18,9 +19,7 @@ func RunCommand(cmd string, args []string, dir string, stdout, stderr io.Writer,
 
 func mergeEnv(orig []string, new map[string]string) []string {
 	wanted := env2map(orig)
-	for k, v := range new {
-		wanted[k] = v
-	}
+	maps.Copy(wanted, new)
 	return map2env(wanted)
 }
 
diff --git a/go.mod b/go.mod
index 7fdc110..a84a566 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/helmfile/chartify
 
-go 1.26.0
+go 1.27.2
 
 require (
 	github.com/Masterminds/semver/v3 v3.5.0
diff --git a/inject.go b/inject.go
index e4f7868..511c83c 100644
--- a/inject.go
+++ b/inject.go
@@ -11,7 +11,7 @@ type InjectOpts struct {
 }
 
 func (r *Runner) Inject(files []string, o InjectOpts) error {
-	var flagsTemplate string
+	var flagsTemplate strings.Builder
 	for _, inj := range o.injectors {
 		tokens := strings.Split(inj, ",")
 		injector := tokens[0]
@@ -20,16 +20,16 @@ func (r *Runner) Inject(files []string, o InjectOpts) error {
 			flagSplit := strings.Split(flag, "=")
 			switch len(flagSplit) {
 			case 1:
-				flagsTemplate += flagSplit[0]
+				flagsTemplate.WriteString(flagSplit[0])
 			case 2:
 				key, val := flagSplit[0], flagSplit[1]
-				flagsTemplate += createFlagChain(key, []string{val})
+				flagsTemplate.WriteString(createFlagChain(key, []string{val}))
 			default:
 				return fmt.Errorf("inject-flags must be in the form of key1=value1[,key2=value2,...]: %v", flag)
 			}
 		}
 		for _, file := range files {
-			flags := strings.Replace(flagsTemplate, "FILE", file, 1)
+			flags := strings.Replace(flagsTemplate.String(), "FILE", file, 1)
 			command := fmt.Sprintf("%s %s", injector, flags)
 			stdout, err := r.runBytes(nil, "", command)
 			if err != nil {
diff --git a/kustomize_extra_args_test.go b/kustomize_extra_args_test.go
index 1c7c65e..49db5f8 100644
--- a/kustomize_extra_args_test.go
+++ b/kustomize_extra_args_test.go
@@ -4,6 +4,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"slices"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -47,10 +48,8 @@ func newSpyRunner(t *testing.T, versionOut string) (*Runner, *[]spyCall) {
 // buildCall returns the first recorded invocation that runs a kustomize "build".
 func buildCall(calls []spyCall) (spyCall, bool) {
 	for _, c := range calls {
-		for _, a := range c.args {
-			if a == "build" {
-				return c, true
-			}
+		if slices.Contains(c.args, "build") {
+			return c, true
 		}
 	}
 	return spyCall{}, false
diff --git a/patch.go b/patch.go
index 27ccb8c..4e2a1bd 100644
--- a/patch.go
+++ b/patch.go
@@ -512,9 +512,9 @@ func (r *Runner) resolveTransformerFileRefs(transformerBytes []byte, transformer
 	// A transformer file can be a single document, a list of documents, or multi-document YAML.
 	decoder := yaml.NewDecoder(bytes.NewReader(transformerBytes))
 
-	var docs []interface{}
+	var docs []any
 	for {
-		var doc interface{}
+		var doc any
 		if err := decoder.Decode(&doc); err != nil {
 			if err == io.EOF {
 				break
@@ -532,14 +532,14 @@ func (r *Runner) resolveTransformerFileRefs(transformerBytes []byte, transformer
 	// Collect all transformer map nodes. This handles both single-document and
 	// list-of-documents formats. Maps are reference types in Go, so modifying
 	// them below will be reflected when re-encoding docs.
-	var allMaps []map[string]interface{}
+	var allMaps []map[string]any
 	for _, doc := range docs {
 		switch v := doc.(type) {
-		case map[string]interface{}:
+		case map[string]any:
 			allMaps = append(allMaps, v)
-		case []interface{}:
+		case []any:
 			for _, item := range v {
-				if m, ok := item.(map[string]interface{}); ok {
+				if m, ok := item.(map[string]any); ok {
 					allMaps = append(allMaps, m)
 				}
 			}
@@ -655,13 +655,13 @@ func (r *Runner) resolveTransformerPath(pathStr string, transformerFileDir strin
 //	    kind: Deployment
 //
 // See https://github.com/kubernetes-sigs/kustomize/blob/master/examples/inlinePatch.md
-func parsePatchDocuments(content []byte) ([]map[string]interface{}, error) {
+func parsePatchDocuments(content []byte) ([]map[string]any, error) {
 	decoder := yaml.NewDecoder(bytes.NewReader(content))
 
-	var entries []map[string]interface{}
+	var entries []map[string]any
 
 	for {
-		var doc interface{}
+		var doc any
 		if err := decoder.Decode(&doc); err != nil {
 			if err == io.EOF {
 				break
@@ -670,18 +670,18 @@ func parsePatchDocuments(content []byte) ([]map[string]interface{}, error) {
 		}
 
 		switch v := doc.(type) {
-		case map[string]interface{}:
+		case map[string]any:
 			if v == nil {
 				// Skip null documents (e.g. from empty "---" separators).
 				continue
 			}
 			entries = append(entries, v)
-		case []interface{}:
+		case []any:
 			if len(v) == 0 {
 				return nil, fmt.Errorf("patches list is empty")
 			}
 			for i, item := range v {
-				m, ok := item.(map[string]interface{})
+				m, ok := item.(map[string]any)
 				if !ok {
 					return nil, fmt.Errorf("patches list item %d must be a YAML mapping, got %T", i, item)
 				}
@@ -705,7 +705,7 @@ func parsePatchDocuments(content []byte) ([]map[string]interface{}, error) {
 // marshalPatchEntry encodes a single kustomize patches entry as YAML suitable for
 // embedding as a list item under the "patches:" field of kustomization.yaml.
 // The returned string has no leading or trailing whitespace lines.
-func marshalPatchEntry(entry map[string]interface{}) (string, error) {
+func marshalPatchEntry(entry map[string]any) (string, error) {
 	buf := &bytes.Buffer{}
 	encoder := yaml.NewEncoder(buf)
 	encoder.SetIndent(2)
diff --git a/patch_test.go b/patch_test.go
index 40f7c1a..7134113 100644
--- a/patch_test.go
+++ b/patch_test.go
@@ -330,9 +330,9 @@ func TestParsePatchDocuments(t *testing.T) {
 // TestMarshalPatchEntry verifies YAML encoding of a patch entry.
 func TestMarshalPatchEntry(t *testing.T) {
 	t.Run("preserves inline block scalar patch", func(t *testing.T) {
-		entry := map[string]interface{}{
+		entry := map[string]any{
 			"patch": "apiVersion: v1\nkind: ConfigMap\ndata:\n  key: val\n",
-			"target": map[string]interface{}{
+			"target": map[string]any{
 				"kind": "ConfigMap",
 			},
 		}
@@ -347,9 +347,9 @@ func TestMarshalPatchEntry(t *testing.T) {
 	})
 
 	t.Run("preserves path field", func(t *testing.T) {
-		entry := map[string]interface{}{
+		entry := map[string]any{
 			"path": "some-file.yaml",
-			"target": map[string]interface{}{
+			"target": map[string]any{
 				"kind": "Deployment",
 			},
 		}
diff --git a/replace.go b/replace.go
index bbdbb7f..6181f50 100644
--- a/replace.go
+++ b/replace.go
@@ -201,8 +201,8 @@ func (r *Runner) ReplaceWithRendered(name, chartName, chartPath string, o Replac
 			}
 		}
 
-		lines := strings.Split(stdout, "\n")
-		for _, line := range lines {
+		lines := strings.SplitSeq(stdout, "\n")
+		for line := range lines {
 			if strings.HasPrefix(line, "wrote ") {
 				file := strings.Split(line, "wrote ")[1]
 
@@ -245,8 +245,8 @@ func (r *Runner) ReplaceWithRendered(name, chartName, chartPath string, o Replac
 	// should have been downloaded by `helm fetch` that run in an even earlier phase of chartify.
 	if r.IsHelm3() || r.IsHelm4() {
 		type ChartMeta struct {
-			Dependencies []Dependency           `yaml:"dependencies,omitempty"`
-			Data         map[string]interface{} `yaml:",inline"`
+			Dependencies []Dependency   `yaml:"dependencies,omitempty"`
+			Data         map[string]any `yaml:",inline"`
 		}
 		var chartMeta ChartMeta
 
diff --git a/requirements.go b/requirements.go
index ef80a2b..a45f06f 100644
--- a/requirements.go
+++ b/requirements.go
@@ -20,7 +20,7 @@ type Dependency struct {
 	Version    string `yaml:"version,omitempty"`
 	// ImportValues holds the mapping of source values to parent key to be imported. Each item can be a
 	// string or pair of child/parent sublist items.
-	ImportValues []interface{} `yaml:"import-values,omitempty"`
+	ImportValues []any `yaml:"import-values,omitempty"`
 }
 
 type ChartDependency struct {
@@ -64,8 +64,8 @@ func (r *Runner) UpdateRequirements(replace bool, chartYamlPath, tempDir string,
 
 	if r.IsHelm3() || r.IsHelm4() {
 		type ChartMeta struct {
-			Dependencies []Dependency           `yaml:"dependencies,omitempty"`
-			Data         map[string]interface{} `yaml:",inline"`
+			Dependencies []Dependency   `yaml:"dependencies,omitempty"`
+			Data         map[string]any `yaml:",inline"`
 		}
 		var chartMeta ChartMeta
 
diff --git a/runner.go b/runner.go
index 8bf0827..f426203 100644
--- a/runner.go
+++ b/runner.go
@@ -35,7 +35,7 @@ type Runner struct {
 	Exists      func(path string) (bool, error)
 
 	// Logf is the alternative log function used by chartify
-	Logf func(string, ...interface{})
+	Logf func(string, ...any)
 }
 
 type Option func(*Runner) error
@@ -61,7 +61,7 @@ func UseHelm4(u bool) Option {
 	}
 }
 
-func WithLogf(logf func(string, ...interface{})) Option {
+func WithLogf(logf func(string, ...any)) Option {
 	return func(r *Runner) error {
 		r.Logf = logf
 		return nil
@@ -259,6 +259,6 @@ func (r *Runner) captureBytes(binary string, args []string, dir string, envs map
 	return stdout.Bytes(), stderr.Bytes(), err
 }
 
-func printf(format string, vars ...interface{}) {
+func printf(format string, vars ...any) {
 	fmt.Fprintf(os.Stderr, format+"\n", vars...)
 }
diff --git a/tempdir.go b/tempdir.go
index da3746c..7ba1136 100644
--- a/tempdir.go
+++ b/tempdir.go
@@ -42,7 +42,7 @@ func makeTempDir(release, chart string, opts *ChartifyOpts) string {
 	d := filepath.Join(workDir, id)
 
 	if os.Getenv(EnvVarDebug) != "" {
-		bs, _ := json.Marshal(map[string]interface{}{
+		bs, _ := json.Marshal(map[string]any{
 			"Release": release,
 			"Chart":   chart,
 			"Options": opts,
@@ -74,7 +74,7 @@ func GenerateID(release, chart string, opts *ChartifyOpts) (string, error) {
 
 	id = append(id, release)
 
-	hash, err := HashObject([]interface{}{release, chart, opts})
+	hash, err := HashObject([]any{release, chart, opts})
 	if err != nil {
 		return "", err
 	}
@@ -84,7 +84,7 @@ func GenerateID(release, chart string, opts *ChartifyOpts) (string, error) {
 	return strings.Join(id, "-"), nil
 }
 
-func HashObject(obj interface{}) (string, error) {
+func HashObject(obj any) (string, error) {
 	hash := fnv.New32a()
 
 	hash.Reset()