Fix UTC labeling of server build time in version output

cli/commands/upgrade_helpers.go

@@ -131,15 +131,15 @@ func PrintVersionComparison(current, latest release.VersionInfo) {
 		fmt.Printf("Current commit:  %s\n", sc)
 	}
 	if !current.BuildDate.IsZero() {
-		fmt.Printf("Current build:   %s\n", current.BuildDate.Format("2006-01-02 15:04:05 UTC"))
+		fmt.Printf("Current build:   %s\n", current.BuildDate.UTC().Format("2006-01-02 15:04:05 UTC"))
 	}
 
 	fmt.Printf("\nLatest version:  %s\n", latest.Version)
 	if sc := latest.ShortCommit(); sc != "" {
 		fmt.Printf("Latest commit:   %s\n", sc)
 	}
 	if !latest.BuildDate.IsZero() {
-		fmt.Printf("Latest build:    %s\n", latest.BuildDate.Format("2006-01-02 15:04:05 UTC"))
+		fmt.Printf("Latest build:    %s\n", latest.BuildDate.UTC().Format("2006-01-02 15:04:05 UTC"))
 	}
 }
 
@@ -164,8 +164,8 @@ func CheckIfUpgradeNeeded(ctx context.Context, targetVersion string, force bool,
 		} else {
 			fmt.Printf("Current version %s is already up to date (target: %s)\n", current.Version, latest.Version)
 			if !current.BuildDate.IsZero() && !latest.BuildDate.IsZero() {
-				fmt.Printf("Current build: %s\n", current.BuildDate.Format("2006-01-02 15:04:05 UTC"))
-				fmt.Printf("Target build:  %s\n", latest.BuildDate.Format("2006-01-02 15:04:05 UTC"))
+				fmt.Printf("Current build: %s\n", current.BuildDate.UTC().Format("2006-01-02 15:04:05 UTC"))
+				fmt.Printf("Target build:  %s\n", latest.BuildDate.UTC().Format("2006-01-02 15:04:05 UTC"))
 			}
 		}
 		return false, nil

cli/commands/upgrade_helpers_test.go

@@ -1,10 +1,15 @@
 package commands
 
 import (
+	"io"
+	"os"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+
+	"miren.dev/runtime/pkg/release"
 )
 
 func TestResolveVersionChannel(t *testing.T) {
@@ -60,3 +65,21 @@ func TestResolveVersionChannel(t *testing.T) {
 		})
 	}
 }
+
+func TestPrintVersionComparisonBuildDatesUTC(t *testing.T) {
+	stdout := os.Stdout
+	r, w, err := os.Pipe()
+	require.NoError(t, err)
+	os.Stdout = w
+	defer func() { os.Stdout = stdout }()
+	defer r.Close()
+
+	PrintVersionComparison(
+		release.VersionInfo{Version: "v1", BuildDate: time.Date(2026, 9, 14, 12, 48, 18, 0, time.FixedZone("CDT", -5*60*60))},
+		release.VersionInfo{Version: "v2", BuildDate: time.Date(2026, 9, 15, 4, 10, 17, 0, time.FixedZone("JST", 9*60*60))},
+	)
+	require.NoError(t, w.Close())
+	output, err := io.ReadAll(r)
+	require.NoError(t, err)
+	assert.Equal(t, "Current version: v1\nCurrent build:   2026-09-14 17:48:18 UTC\n\nLatest version:  v2\nLatest build:    2026-09-14 19:10:17 UTC\n", string(output))
+}

cli/commands/version.go

@@ -145,7 +145,7 @@ func printBuildLines(ctx *Context, ver, commit string, built time.Time) {
 		ctx.Printf("  Commit:   %s\n", commit)
 	}
 	if !built.IsZero() {
-		ctx.Printf("  Built:    %s\n", built.Format("2006-01-02 15:04:05 UTC"))
+		ctx.Printf("  Built:    %s\n", built.UTC().Format("2006-01-02 15:04:05 UTC"))
 	}
 }
 

cli/commands/version_test.go

@@ -0,0 +1,39 @@
+package commands
+
+import (
+	"bytes"
+	"testing"
+	"time"
+)
+
+func TestPrintBuildLinesUTC(t *testing.T) {
+	tests := []struct {
+		name  string
+		built time.Time
+		want  string
+	}{
+		{
+			name:  "server build in local timezone",
+			built: time.Date(2026, 9, 14, 12, 48, 18, 0, time.FixedZone("CDT", -5*60*60)),
+			want:  "  Version:  v1\n  Built:    2026-09-14 17:48:18 UTC\n",
+		},
+		{
+			name:  "CLI build already in UTC",
+			built: time.Date(2026, 9, 14, 18, 10, 17, 0, time.UTC),
+			want:  "  Version:  v1\n  Built:    2026-09-14 18:10:17 UTC\n",
+		},
+		{
+			name: "unknown build date",
+			want: "  Version:  v1\n",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var out bytes.Buffer
+			printBuildLines(&Context{Stdout: &out}, "v1", "", tt.built)
+			if got := out.String(); got != tt.want {
+				t.Fatalf("printBuildLines output = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}