diff --git a/android/app/build.gradle.kts b/android/app/build.gradle.kts
index fff7ac8..7293162 100644
--- a/android/app/build.gradle.kts
+++ b/android/app/build.gradle.kts
@@ -48,6 +48,11 @@ android {
         }
         release {
             if (releaseStoreFile != null) signingConfig = signingConfigs.getByName("release")
+            // SPEC §10.6: R8 shrinks, optimises and obfuscates the release APK; the libraries' consumer rules plus
+            // proguard-rules.pro. publish-apk.sh keeps build/outputs/mapping/release/mapping.txt next to the APK.
+            isMinifyEnabled = true
+            isShrinkResources = true
+            proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
         }
     }
     sourceSets {
diff --git a/android/app/proguard-rules.pro b/android/app/proguard-rules.pro
new file mode 100644
index 0000000..ef43999
--- /dev/null
+++ b/android/app/proguard-rules.pro
@@ -0,0 +1,3 @@
+# R8 rules for the release build of :app (SPEC §10.6). The libraries in use (kotlinx.serialization, Room 3, Hilt,
+# Ktor, OkHttp, WorkManager, Firebase messaging, Coil) ship their own consumer rules; add a rule here only for a
+# failure that was seen and with the reason beside it.