diff --git a/Jenkinsfile.release b/Jenkinsfile.release
index a8adf17..2cdd1b0 100644
--- a/Jenkinsfile.release
+++ b/Jenkinsfile.release
@@ -4,8 +4,8 @@ pipeline {
     parameters {
         string(
             name: 'IOS_BUILD_NUMBER',
-            defaultValue: '2',
-            description: 'Positive, monotonically increasing App Store build number.'
+            defaultValue: '',
+            description: 'Optional App Store build number override. Blank uses the Jenkins build number.'
         )
     }
 
@@ -41,7 +41,7 @@ pipeline {
 
         stage('Signed iOS IPA') {
             steps {
-                sh './scripts/ci/build-ios-signed.sh "$IOS_BUILD_NUMBER"'
+                sh './scripts/ci/build-ios-signed.sh "${IOS_BUILD_NUMBER:-$BUILD_NUMBER}"'
             }
         }
     }
diff --git a/doc/iOS_TestFlight.md b/doc/iOS_TestFlight.md
index 054fa60..e18fbd6 100644
--- a/doc/iOS_TestFlight.md
+++ b/doc/iOS_TestFlight.md
@@ -45,10 +45,11 @@ the installed `UM Trace App Store` profile, and prints the generated `.ipa` path
 
 ## Create a signed IPA in Jenkins
 
-The manually run `um-trace-ios-release` pipeline uses `Jenkinsfile.release`. Supply an
-`IOS_BUILD_NUMBER` that is higher than every build previously uploaded to App Store Connect. The
-pipeline runs the tests, signs with the distribution identity and `UM Trace App Store` profile,
-verifies the resulting bundle signature and identity, and archives the IPA plus its SHA-256 file.
+The manually run `um-trace-ios-release` pipeline uses `Jenkinsfile.release`. By default it uses the
+monotonically increasing Jenkins build number as the App Store build number. Set
+`IOS_BUILD_NUMBER` only when an explicit higher override is required. The pipeline runs the tests,
+signs with the distribution identity and `UM Trace App Store` profile, verifies the resulting
+bundle signature and identity, and archives the IPA plus its SHA-256 file.
 
 This pipeline only creates a signed artifact. It does not upload or submit anything to App Store
 Connect, so TestFlight release remains a separate, deliberate step.