diff --git a/lib/__tests__/apk-parser.test.ts b/lib/__tests__/apk-parser.test.ts
index ab0d4c5..c351ac0 100644
--- a/lib/__tests__/apk-parser.test.ts
+++ b/lib/__tests__/apk-parser.test.ts
@@ -8,9 +8,9 @@ describe('parseApkFilename', () => {
     expect(result.isValid).toBe(true);
   });
 
-  it('should parse APK with version number segment (no environment suffix)', () => {
+  it('should parse APK without environment (product)', () => {
     const result = parseApkFilename('ft_0_42_ff9ff3441.apk');
-    expect(result.environment).toBe('other');
+    expect(result.environment).toBe('product');
     expect(result.commit).toBe('ff9ff3441');
     expect(result.isValid).toBe(true);
   });
@@ -46,8 +46,8 @@ describe('detectEnvironment', () => {
     expect(detectEnvironment('ft_sandbox_0_42_57ef3a60d.apk')).toBe('sandbox');
   });
 
-  it('should detect other for version number segment', () => {
-    expect(detectEnvironment('ft_0_42_ff9ff3441.apk')).toBe('other');
+  it('should detect product environment (no suffix)', () => {
+    expect(detectEnvironment('ft_0_42_ff9ff3441.apk')).toBe('product');
   });
 
   it('should detect lan environment', () => {
diff --git a/lib/apk-parser.ts b/lib/apk-parser.ts
index f5561bb..fd6a712 100644
--- a/lib/apk-parser.ts
+++ b/lib/apk-parser.ts
@@ -16,8 +16,8 @@ const ENVIRONMENT_MAP: Record<string, ApkEnvironment> = {
 
 export function detectEnvironment(filename: string): ApkEnvironment {
   // Pattern: ft_[environment]_version_commit.apk
-  // Extract the environment segment between first and second underscores
-  const match = filename.match(/^ft_([^_]+)_/);
+  // Extract the environment segment (alphabetic only) between first and second underscores
+  const match = filename.match(/^ft_([a-z]+)_/i);
 
   if (!match) {
     // No environment suffix, default to product