diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index cff1192..95010a1 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -53,7 +53,7 @@ android {
 
     buildTypes {
         debug {
-            // applicationIdSuffix = ".dev"  // Temporarily disabled for one-time migration
+            applicationIdSuffix = ".dev"
             resValue("string", "app_name", "Podometer-dev")
         }
         release {
diff --git a/app/src/main/java/com/podometer/data/db/SensorWindowDao.kt b/app/src/main/java/com/podometer/data/db/SensorWindowDao.kt
index 53995e3..5f74c84 100644
--- a/app/src/main/java/com/podometer/data/db/SensorWindowDao.kt
+++ b/app/src/main/java/com/podometer/data/db/SensorWindowDao.kt
@@ -19,6 +19,10 @@ interface SensorWindowDao {
     @Insert
     suspend fun insert(window: SensorWindow)
 
+    /** Inserts multiple sensor window rows. */
+    @Insert
+    suspend fun insertAll(windows: List<SensorWindow>)
+
     /**
      * Returns all sensor windows whose [SensorWindow.timestamp] falls within
      * [[startMs], [endMs]] (inclusive), ordered by timestamp ascending.
diff --git a/app/src/main/java/com/podometer/di/UseCaseModule.kt b/app/src/main/java/com/podometer/di/UseCaseModule.kt
index 99f1f77..7755994 100644
--- a/app/src/main/java/com/podometer/di/UseCaseModule.kt
+++ b/app/src/main/java/com/podometer/di/UseCaseModule.kt
@@ -112,10 +112,12 @@ abstract class UseCaseModule {
             stepDao: StepDao,
             activityTransitionDao: ActivityTransitionDao,
             cyclingSessionDao: CyclingSessionDao,
+            sensorWindowDao: SensorWindowDao,
         ): ImportDataUseCase = ImportDataUseCase(
             stepDao = stepDao,
             activityTransitionDao = activityTransitionDao,
             cyclingSessionDao = cyclingSessionDao,
+            sensorWindowDao = sensorWindowDao,
         )
     }
 }
diff --git a/app/src/main/java/com/podometer/domain/usecase/ImportDataUseCase.kt b/app/src/main/java/com/podometer/domain/usecase/ImportDataUseCase.kt
index 1f7d2bc..9d65c3f 100644
--- a/app/src/main/java/com/podometer/domain/usecase/ImportDataUseCase.kt
+++ b/app/src/main/java/com/podometer/domain/usecase/ImportDataUseCase.kt
@@ -7,6 +7,8 @@ import com.podometer.data.db.CyclingSession
 import com.podometer.data.db.CyclingSessionDao
 import com.podometer.data.db.DailySummary
 import com.podometer.data.db.HourlyStepAggregate
+import com.podometer.data.db.SensorWindow
+import com.podometer.data.db.SensorWindowDao
 import com.podometer.data.db.StepDao
 import com.podometer.data.export.ExportData
 import kotlinx.serialization.json.Json
@@ -20,11 +22,13 @@ import kotlinx.serialization.json.Json
  * @param stepDao DAO for daily summaries and hourly aggregates.
  * @param activityTransitionDao DAO for activity transitions.
  * @param cyclingSessionDao DAO for cycling sessions.
+ * @param sensorWindowDao DAO for raw sensor classifier windows.
  */
 class ImportDataUseCase(
     private val stepDao: StepDao,
     private val activityTransitionDao: ActivityTransitionDao,
     private val cyclingSessionDao: CyclingSessionDao,
+    private val sensorWindowDao: SensorWindowDao,
 ) {
 
     private val json = Json { ignoreUnknownKeys = true }
@@ -84,5 +88,17 @@ class ImportDataUseCase(
                 )
             },
         )
+
+        sensorWindowDao.insertAll(
+            data.sensorWindows.map { w ->
+                SensorWindow(
+                    id = 0,
+                    timestamp = w.timestamp,
+                    magnitudeVariance = w.magnitudeVariance,
+                    stepFrequencyHz = w.stepFrequencyHz,
+                    stepCount = w.stepCount,
+                )
+            },
+        )
     }
 }
diff --git a/app/src/test/java/com/podometer/domain/usecase/ExportDataUseCaseTest.kt b/app/src/test/java/com/podometer/domain/usecase/ExportDataUseCaseTest.kt
index 1c20efe..35d05d3 100644
--- a/app/src/test/java/com/podometer/domain/usecase/ExportDataUseCaseTest.kt
+++ b/app/src/test/java/com/podometer/domain/usecase/ExportDataUseCaseTest.kt
@@ -116,6 +116,7 @@ class ExportDataUseCaseTest {
 
     private class FakeSensorWindowDao : SensorWindowDao {
         override suspend fun insert(window: SensorWindow) = Unit
+        override suspend fun insertAll(windows: List<SensorWindow>) = Unit
         override fun getWindowsBetween(startMs: Long, endMs: Long): Flow<List<SensorWindow>> =
             flowOf(emptyList())
         override suspend fun getAllWindows(): List<SensorWindow> = emptyList()