diff --git a/.github/workflows/android-build.yml b/.github/workflows/android-build.yml
index da5d00d..2a12a48 100644
--- a/.github/workflows/android-build.yml
+++ b/.github/workflows/android-build.yml
@@ -26,16 +26,10 @@ jobs:
       - name: Set up Gradle
         uses: gradle/actions/setup-gradle@v4
 
-      - name: Cache Android debug keystore
-        uses: actions/cache@v4
-        with:
-          path: ~/.android/debug.keystore
-          key: android-debug-keystore-${{ runner.os }}
-
       - name: Make Gradle wrapper executable
         run: chmod +x gradlew
 
-      - name: Build debug APK
+      - name: Build update-compatible APK
         run: ./gradlew assembleDebug -PciVersionCode=${{ github.run_number }} -PciVersionName=1.0.${{ github.run_number }}
 
       - name: Prepare release assets
diff --git a/app/build.gradle b/app/build.gradle
index 72d0204..4341226 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -4,11 +4,21 @@ plugins {
 
 def ciVersionCode = providers.gradleProperty("ciVersionCode").getOrNull()
 def ciVersionName = providers.gradleProperty("ciVersionName").getOrNull()
+def sharedDebugKeystore = file("signing/bible-daily-debug.keystore")
 
 android {
     namespace "com.bibliadiaria.app"
     compileSdk 35
 
+    signingConfigs {
+        sharedDebug {
+            storeFile sharedDebugKeystore
+            storePassword "android"
+            keyAlias "androiddebugkey"
+            keyPassword "android"
+        }
+    }
+
     defaultConfig {
         applicationId "com.bibliadiaria.app"
         minSdk 23
@@ -17,6 +27,14 @@ android {
         versionName ciVersionName != null ? ciVersionName : "1.0"
     }
 
+    buildTypes {
+        debug {
+            if (sharedDebugKeystore.exists()) {
+                signingConfig signingConfigs.sharedDebug
+            }
+        }
+    }
+
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_17
         targetCompatibility JavaVersion.VERSION_17
diff --git a/app/signing/README.md b/app/signing/README.md
new file mode 100644
index 0000000..1dc0325
--- /dev/null
+++ b/app/signing/README.md
@@ -0,0 +1,3 @@
+This debug keystore is intentionally shared by local and GitHub Actions builds so sideloaded APK updates keep the same Android signing identity.
+
+Do not use this key for Play Store or production release signing.
diff --git a/app/signing/bible-daily-debug.keystore b/app/signing/bible-daily-debug.keystore
new file mode 100644
index 0000000..dd872c6
Binary files /dev/null and b/app/signing/bible-daily-debug.keystore differ
diff --git a/build/reports/problems/problems-report.html b/build/reports/problems/problems-report.html
index 085cc1c..ae3aa1c 100644
--- a/build/reports/problems/problems-report.html
+++ b/build/reports/problems/problems-report.html
@@ -650,7 +650,7 @@ code + .copy-button {
 <script type="text/javascript">
 function configurationCacheProblems() { return (
 // begin-report-data
-{"diagnostics":[{"problem":[{"text":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"severity":"WARNING","problemDetails":[{"text":"This is scheduled to be removed in Gradle 10."}],"contextualLabel":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated.","documentationLink":"https://docs.gradle.org/9.0.0/userguide/upgrading_version_8.html#groovy_space_assignment_syntax","problemId":[{"name":"deprecation","displayName":"Deprecation"},{"name":"properties-should-be-assigned-using-the-propname-value-syntax-setting-a-property-via-the-gradle-generated-propname-value-or-propname-value-syntax-in-groovy-dsl","displayName":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"solutions":[[{"text":"Use assignment ('namespace = <value>') instead."}]]},{"problem":[{"text":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"severity":"WARNING","problemDetails":[{"text":"This is scheduled to be removed in Gradle 10."}],"contextualLabel":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated.","documentationLink":"https://docs.gradle.org/9.0.0/userguide/upgrading_version_8.html#groovy_space_assignment_syntax","problemId":[{"name":"deprecation","displayName":"Deprecation"},{"name":"properties-should-be-assigned-using-the-propname-value-syntax-setting-a-property-via-the-gradle-generated-propname-value-or-propname-value-syntax-in-groovy-dsl","displayName":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"solutions":[[{"text":"Use assignment ('compileSdk = <value>') instead."}]]},{"problem":[{"text":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"severity":"WARNING","problemDetails":[{"text":"This is scheduled to be removed in Gradle 10."}],"contextualLabel":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated.","documentationLink":"https://docs.gradle.org/9.0.0/userguide/upgrading_version_8.html#groovy_space_assignment_syntax","problemId":[{"name":"deprecation","displayName":"Deprecation"},{"name":"properties-should-be-assigned-using-the-propname-value-syntax-setting-a-property-via-the-gradle-generated-propname-value-or-propname-value-syntax-in-groovy-dsl","displayName":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"solutions":[[{"text":"Use assignment ('minSdk = <value>') instead."}]]},{"problem":[{"text":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"severity":"WARNING","problemDetails":[{"text":"This is scheduled to be removed in Gradle 10."}],"contextualLabel":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated.","documentationLink":"https://docs.gradle.org/9.0.0/userguide/upgrading_version_8.html#groovy_space_assignment_syntax","problemId":[{"name":"deprecation","displayName":"Deprecation"},{"name":"properties-should-be-assigned-using-the-propname-value-syntax-setting-a-property-via-the-gradle-generated-propname-value-or-propname-value-syntax-in-groovy-dsl","displayName":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"solutions":[[{"text":"Use assignment ('targetSdk = <value>') instead."}]]},{"locations":[{"path":"C:\\Users\\360he\\Documents\\Bible app\\app\\src\\main\\java\\com\\bibliadiaria\\app\\ExtrasActivity.java"},{"taskPath":":app:compileDebugJavaWithJavac"}],"problem":[{"text":"Some input files use or override a deprecated API."}],"severity":"ADVICE","problemDetails":[{"text":"Note: Some input files use or override a deprecated API."}],"contextualLabel":"Some input files use or override a deprecated API.","problemId":[{"name":"java","displayName":"Java compilation"},{"name":"compilation","displayName":"Compilation"},{"name":"compiler.note.deprecated.plural","displayName":"Some input files use or override a deprecated API."}]},{"locations":[{"path":"C:\\Users\\360he\\Documents\\Bible app\\app\\src\\main\\java\\com\\bibliadiaria\\app\\ExtrasActivity.java"},{"taskPath":":app:compileDebugJavaWithJavac"}],"problem":[{"text":"Recompile with -Xlint:deprecation for details."}],"severity":"ADVICE","problemDetails":[{"text":"Note: Recompile with -Xlint:deprecation for details."}],"contextualLabel":"Recompile with -Xlint:deprecation for details.","problemId":[{"name":"java","displayName":"Java compilation"},{"name":"compilation","displayName":"Compilation"},{"name":"compiler.note.deprecated.recompile","displayName":"Recompile with -Xlint:deprecation for details."}]}],"problemsReport":{"totalProblemCount":6,"buildName":"Biblia Diaria","requestedTasks":"assembleDebug","documentationLink":"https://docs.gradle.org/9.0.0/userguide/reporting_problems.html","documentationLinkCaption":"Problem report","summaries":[]}}
+{"diagnostics":[{"problem":[{"text":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"severity":"WARNING","problemDetails":[{"text":"This is scheduled to be removed in Gradle 10."}],"contextualLabel":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated.","documentationLink":"https://docs.gradle.org/9.0.0/userguide/upgrading_version_8.html#groovy_space_assignment_syntax","problemId":[{"name":"deprecation","displayName":"Deprecation"},{"name":"properties-should-be-assigned-using-the-propname-value-syntax-setting-a-property-via-the-gradle-generated-propname-value-or-propname-value-syntax-in-groovy-dsl","displayName":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"solutions":[[{"text":"Use assignment ('namespace = <value>') instead."}]]},{"problem":[{"text":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"severity":"WARNING","problemDetails":[{"text":"This is scheduled to be removed in Gradle 10."}],"contextualLabel":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated.","documentationLink":"https://docs.gradle.org/9.0.0/userguide/upgrading_version_8.html#groovy_space_assignment_syntax","problemId":[{"name":"deprecation","displayName":"Deprecation"},{"name":"properties-should-be-assigned-using-the-propname-value-syntax-setting-a-property-via-the-gradle-generated-propname-value-or-propname-value-syntax-in-groovy-dsl","displayName":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"solutions":[[{"text":"Use assignment ('compileSdk = <value>') instead."}]]},{"problem":[{"text":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"severity":"WARNING","problemDetails":[{"text":"This is scheduled to be removed in Gradle 10."}],"contextualLabel":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated.","documentationLink":"https://docs.gradle.org/9.0.0/userguide/upgrading_version_8.html#groovy_space_assignment_syntax","problemId":[{"name":"deprecation","displayName":"Deprecation"},{"name":"properties-should-be-assigned-using-the-propname-value-syntax-setting-a-property-via-the-gradle-generated-propname-value-or-propname-value-syntax-in-groovy-dsl","displayName":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"solutions":[[{"text":"Use assignment ('minSdk = <value>') instead."}]]},{"problem":[{"text":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"severity":"WARNING","problemDetails":[{"text":"This is scheduled to be removed in Gradle 10."}],"contextualLabel":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated.","documentationLink":"https://docs.gradle.org/9.0.0/userguide/upgrading_version_8.html#groovy_space_assignment_syntax","problemId":[{"name":"deprecation","displayName":"Deprecation"},{"name":"properties-should-be-assigned-using-the-propname-value-syntax-setting-a-property-via-the-gradle-generated-propname-value-or-propname-value-syntax-in-groovy-dsl","displayName":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"solutions":[[{"text":"Use assignment ('targetSdk = <value>') instead."}]]},{"problem":[{"text":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"severity":"WARNING","problemDetails":[{"text":"This is scheduled to be removed in Gradle 10."}],"contextualLabel":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated.","documentationLink":"https://docs.gradle.org/9.0.0/userguide/upgrading_version_8.html#groovy_space_assignment_syntax","problemId":[{"name":"deprecation","displayName":"Deprecation"},{"name":"properties-should-be-assigned-using-the-propname-value-syntax-setting-a-property-via-the-gradle-generated-propname-value-or-propname-value-syntax-in-groovy-dsl","displayName":"Properties should be assigned using the 'propName = value' syntax. Setting a property via the Gradle-generated 'propName value' or 'propName(value)' syntax in Groovy DSL has been deprecated."}],"solutions":[[{"text":"Use assignment ('signingConfig = <value>') instead."}]]}],"problemsReport":{"totalProblemCount":5,"buildName":"Biblia Diaria","requestedTasks":"assembleDebug","documentationLink":"https://docs.gradle.org/9.0.0/userguide/reporting_problems.html","documentationLinkCaption":"Problem report","summaries":[]}}
 // end-report-data
 );}
 </script>