diff --git a/github.go b/github.go
index 31354f1..03b4cd7 100644
--- a/github.go
+++ b/github.go
@@ -50,7 +50,7 @@ type githubClient struct{}
 var NewAuthenticatedClient = func(ctx context.Context) *http.Client {
 	token := os.Getenv("GITHUB_TOKEN")
 	if token == "" {
-		return NewHTTPClient()
+		return http.DefaultClient
 	}
 
 	ts := oauth2.StaticTokenSource(
diff --git a/github_internal_test.go b/github_internal_test.go
index 2024f37..09f301e 100644
--- a/github_internal_test.go
+++ b/github_internal_test.go
@@ -82,6 +82,54 @@ func TestDetermineChannel_Good(t *testing.T) {
 	}
 }
 
+func TestCheckForUpdatesByTag_UsesCurrentVersionChannel(t *testing.T) {
+	originalVersion := Version
+	originalCheckForUpdates := CheckForUpdates
+	defer func() {
+		Version = originalVersion
+		CheckForUpdates = originalCheckForUpdates
+	}()
+
+	var gotChannel string
+	CheckForUpdates = func(owner, repo, channel string, forceSemVerPrefix bool, releaseURLFormat string) error {
+		gotChannel = channel
+		return nil
+	}
+
+	Version = "v2.0.0-rc.1"
+	if err := CheckForUpdatesByTag("owner", "repo"); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if gotChannel != "beta" {
+		t.Fatalf("expected beta channel, got %q", gotChannel)
+	}
+}
+
+func TestCheckOnlyByTag_UsesCurrentVersionChannel(t *testing.T) {
+	originalVersion := Version
+	originalCheckOnly := CheckOnly
+	defer func() {
+		Version = originalVersion
+		CheckOnly = originalCheckOnly
+	}()
+
+	var gotChannel string
+	CheckOnly = func(owner, repo, channel string, forceSemVerPrefix bool, releaseURLFormat string) error {
+		gotChannel = channel
+		return nil
+	}
+
+	Version = "v2.0.0-alpha.1"
+	if err := CheckOnlyByTag("owner", "repo"); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if gotChannel != "alpha" {
+		t.Fatalf("expected alpha channel, got %q", gotChannel)
+	}
+}
+
 func TestGetDownloadURL_Good(t *testing.T) {
 	osName := runtime.GOOS
 	archName := runtime.GOARCH
diff --git a/service.go b/service.go
index a58f448..737e22b 100644
--- a/service.go
+++ b/service.go
@@ -63,6 +63,7 @@ func NewUpdateService(config UpdateServiceConfig) (*UpdateService, error) {
 	var err error
 
 	if isGitHub {
+		config.Channel = normaliseGitHubChannel(config.Channel)
 		owner, repo, err = ParseRepoURL(config.RepoURL)
 		if err != nil {
 			return nil, coreerr.E("NewUpdateService", "failed to parse GitHub repo URL", err)
@@ -127,3 +128,11 @@ func ParseRepoURL(repoURL string) (owner string, repo string, err error) {
 	}
 	return parts[0], parts[1], nil
 }
+
+func normaliseGitHubChannel(channel string) string {
+	channel = strings.ToLower(strings.TrimSpace(channel))
+	if channel == "" {
+		return "stable"
+	}
+	return channel
+}
diff --git a/service_test.go b/service_test.go
index ab8691a..c65458c 100644
--- a/service_test.go
+++ b/service_test.go
@@ -12,13 +12,15 @@ func TestNewUpdateService(t *testing.T) {
 		config      UpdateServiceConfig
 		expectError bool
 		isGitHub    bool
+		wantChannel string
 	}{
 		{
 			name: "Valid GitHub URL",
 			config: UpdateServiceConfig{
 				RepoURL: "https://github.com/owner/repo",
 			},
-			isGitHub: true,
+			isGitHub:    true,
+			wantChannel: "stable",
 		},
 		{
 			name: "Valid non-GitHub URL",
@@ -27,6 +29,15 @@ func TestNewUpdateService(t *testing.T) {
 			},
 			isGitHub: false,
 		},
+		{
+			name: "GitHub channel is normalised",
+			config: UpdateServiceConfig{
+				RepoURL: "https://github.com/owner/repo",
+				Channel: " Beta ",
+			},
+			isGitHub:    true,
+			wantChannel: "beta",
+		},
 		{
 			name: "Invalid GitHub URL",
 			config: UpdateServiceConfig{
@@ -45,6 +56,9 @@ func TestNewUpdateService(t *testing.T) {
 			if err == nil && service.isGitHub != tc.isGitHub {
 				t.Errorf("Expected isGitHub: %v, got: %v", tc.isGitHub, service.isGitHub)
 			}
+			if err == nil && tc.wantChannel != "" && service.config.Channel != tc.wantChannel {
+				t.Errorf("Expected GitHub channel %q, got %q", tc.wantChannel, service.config.Channel)
+			}
 		})
 	}
 }
diff --git a/updater.go b/updater.go
index 59a82d7..99858f3 100644
--- a/updater.go
+++ b/updater.go
@@ -145,14 +145,14 @@ var CheckOnly = func(owner, repo, channel string, forceSemVerPrefix bool, releas
 // CheckForUpdatesByTag checks for and applies updates from GitHub based on the channel
 // determined by the current application's version tag (e.g., 'stable' or 'prerelease').
 var CheckForUpdatesByTag = func(owner, repo string) error {
-	channel := determineChannel(Version, false) // isPreRelease is false for current version
+	channel := determineChannel(Version, semver.Prerelease(formatVersionForComparison(Version)) != "")
 	return CheckForUpdates(owner, repo, channel, true, "")
 }
 
 // CheckOnlyByTag checks for updates from GitHub based on the channel determined by the
 // current version tag, without applying them.
 var CheckOnlyByTag = func(owner, repo string) error {
-	channel := determineChannel(Version, false) // isPreRelease is false for current version
+	channel := determineChannel(Version, semver.Prerelease(formatVersionForComparison(Version)) != "")
 	return CheckOnly(owner, repo, channel, true, "")
 }