diff --git a/app/src/main/java/com/bitchat/android/mesh/BluetoothConnectionTracker.kt b/app/src/main/java/com/bitchat/android/mesh/BluetoothConnectionTracker.kt
index f7e7d7a6..0f0bdd86 100644
--- a/app/src/main/java/com/bitchat/android/mesh/BluetoothConnectionTracker.kt
+++ b/app/src/main/java/com/bitchat/android/mesh/BluetoothConnectionTracker.kt
@@ -20,10 +20,10 @@ class BluetoothConnectionTracker(
     
     companion object {
         private const val TAG = "BluetoothConnectionTracker"
-        private val CONNECTION_RETRY_DELAY = com.bitchat.android.util.AppConstants.Mesh.CONNECTION_RETRY_DELAY_MS
-        private val MAX_CONNECTION_ATTEMPTS = com.bitchat.android.util.AppConstants.Mesh.MAX_CONNECTION_ATTEMPTS
-        private val CLEANUP_DELAY = com.bitchat.android.util.AppConstants.Mesh.CONNECTION_CLEANUP_DELAY_MS
-        private val CLEANUP_INTERVAL = com.bitchat.android.util.AppConstants.Mesh.CONNECTION_CLEANUP_INTERVAL_MS // 30 seconds
+        private const val CONNECTION_RETRY_DELAY = com.bitchat.android.util.AppConstants.Mesh.CONNECTION_RETRY_DELAY_MS
+        private const val MAX_CONNECTION_ATTEMPTS = com.bitchat.android.util.AppConstants.Mesh.MAX_CONNECTION_ATTEMPTS
+        private const val CLEANUP_DELAY = com.bitchat.android.util.AppConstants.Mesh.CONNECTION_CLEANUP_DELAY_MS
+        private const val CLEANUP_INTERVAL = com.bitchat.android.util.AppConstants.Mesh.CONNECTION_CLEANUP_INTERVAL_MS // 30 seconds
     }
     
     // Connection tracking - reduced memory footprint
diff --git a/app/src/main/java/com/bitchat/android/mesh/BluetoothGattClientManager.kt b/app/src/main/java/com/bitchat/android/mesh/BluetoothGattClientManager.kt
index 1b0eef6b..f263b068 100644
--- a/app/src/main/java/com/bitchat/android/mesh/BluetoothGattClientManager.kt
+++ b/app/src/main/java/com/bitchat/android/mesh/BluetoothGattClientManager.kt
@@ -37,7 +37,7 @@ class BluetoothGattClientManager(
         private val DESCRIPTOR_UUID = UUID.fromString("00002902-0000-1000-8000-00805f9b34fb")
         
         // RSSI monitoring constants
-        private val RSSI_UPDATE_INTERVAL = com.bitchat.android.util.AppConstants.Mesh.RSSI_UPDATE_INTERVAL_MS // 5 seconds
+        private const val RSSI_UPDATE_INTERVAL = com.bitchat.android.util.AppConstants.Mesh.RSSI_UPDATE_INTERVAL_MS // 5 seconds
     }
     
     // Core Bluetooth components
diff --git a/app/src/main/java/com/bitchat/android/mesh/BluetoothPacketBroadcaster.kt b/app/src/main/java/com/bitchat/android/mesh/BluetoothPacketBroadcaster.kt
index 9adbef1b..b3474217 100644
--- a/app/src/main/java/com/bitchat/android/mesh/BluetoothPacketBroadcaster.kt
+++ b/app/src/main/java/com/bitchat/android/mesh/BluetoothPacketBroadcaster.kt
@@ -47,7 +47,7 @@ class BluetoothPacketBroadcaster(
     
     companion object {
         private const val TAG = "BluetoothPacketBroadcaster"
-        private val CLEANUP_DELAY = com.bitchat.android.util.AppConstants.Mesh.BROADCAST_CLEANUP_DELAY_MS
+        private const val CLEANUP_DELAY = com.bitchat.android.util.AppConstants.Mesh.BROADCAST_CLEANUP_DELAY_MS
     }
 
     // Optional nickname resolver injected by higher layer (peerID -> nickname?)
diff --git a/app/src/main/java/com/bitchat/android/mesh/FragmentManager.kt b/app/src/main/java/com/bitchat/android/mesh/FragmentManager.kt
index 82352030..714aedb2 100644
--- a/app/src/main/java/com/bitchat/android/mesh/FragmentManager.kt
+++ b/app/src/main/java/com/bitchat/android/mesh/FragmentManager.kt
@@ -22,10 +22,10 @@ class FragmentManager {
     companion object {
         private const val TAG = "FragmentManager"
         // iOS values: 512 MTU threshold, 469 max fragment size (512 MTU - headers)
-        private val FRAGMENT_SIZE_THRESHOLD = com.bitchat.android.util.AppConstants.Fragmentation.FRAGMENT_SIZE_THRESHOLD // Matches iOS: if data.count > 512
-        private val MAX_FRAGMENT_SIZE = com.bitchat.android.util.AppConstants.Fragmentation.MAX_FRAGMENT_SIZE        // Matches iOS: maxFragmentSize = 469 
-        private val FRAGMENT_TIMEOUT = com.bitchat.android.util.AppConstants.Fragmentation.FRAGMENT_TIMEOUT_MS     // Matches iOS: 30 seconds cleanup
-        private val CLEANUP_INTERVAL = com.bitchat.android.util.AppConstants.Fragmentation.CLEANUP_INTERVAL_MS     // 10 seconds cleanup check
+        private const val FRAGMENT_SIZE_THRESHOLD = com.bitchat.android.util.AppConstants.Fragmentation.FRAGMENT_SIZE_THRESHOLD // Matches iOS: if data.count > 512
+        private const val MAX_FRAGMENT_SIZE = com.bitchat.android.util.AppConstants.Fragmentation.MAX_FRAGMENT_SIZE        // Matches iOS: maxFragmentSize = 469 
+        private const val FRAGMENT_TIMEOUT = com.bitchat.android.util.AppConstants.Fragmentation.FRAGMENT_TIMEOUT_MS     // Matches iOS: 30 seconds cleanup
+        private const val CLEANUP_INTERVAL = com.bitchat.android.util.AppConstants.Fragmentation.CLEANUP_INTERVAL_MS     // 10 seconds cleanup check
     }
     
     // Fragment storage - iOS equivalent: incomingFragments: [String: [Int: Data]]
diff --git a/app/src/main/java/com/bitchat/android/mesh/MessageHandler.kt b/app/src/main/java/com/bitchat/android/mesh/MessageHandler.kt
index d3447e8b..d016dd37 100644
--- a/app/src/main/java/com/bitchat/android/mesh/MessageHandler.kt
+++ b/app/src/main/java/com/bitchat/android/mesh/MessageHandler.kt
@@ -214,8 +214,8 @@ class MessageHandler(private val myPeerID: String, private val appContext: andro
         // Ignore stale announcements older than STALE_PEER_TIMEOUT
         val now = System.currentTimeMillis()
         val age = now - packet.timestamp.toLong()
-        if (age > com.bitchat.android.util.AppConstants.STALE_PEER_TIMEOUT_MS) {
-            Log.w(TAG, "Ignoring stale ANNOUNCE from ${peerID.take(8)} (age=${age}ms > ${com.bitchat.android.util.AppConstants.STALE_PEER_TIMEOUT_MS}ms)")
+        if (age > com.bitchat.android.util.AppConstants.Mesh.STALE_PEER_TIMEOUT_MS) {
+            Log.w(TAG, "Ignoring stale ANNOUNCE from ${peerID.take(8)} (age=${age}ms > ${com.bitchat.android.util.AppConstants.Mesh.STALE_PEER_TIMEOUT_MS}ms)")
             return false
         }
         
diff --git a/app/src/main/java/com/bitchat/android/mesh/PeerManager.kt b/app/src/main/java/com/bitchat/android/mesh/PeerManager.kt
index 03e8e004..4c279d4a 100644
--- a/app/src/main/java/com/bitchat/android/mesh/PeerManager.kt
+++ b/app/src/main/java/com/bitchat/android/mesh/PeerManager.kt
@@ -70,7 +70,7 @@ class PeerManager {
     }
 
     // Centralized timeout from AppConstants
-    private val stalePeerTimeoutMs: Long = com.bitchat.android.util.AppConstants.STALE_PEER_TIMEOUT_MS
+    private val stalePeerTimeoutMs: Long = com.bitchat.android.util.AppConstants.Mesh.STALE_PEER_TIMEOUT_MS
     
     // Peer tracking data - enhanced with verification status
     private val peers = ConcurrentHashMap<String, PeerInfo>() // peerID -> PeerInfo
diff --git a/app/src/main/java/com/bitchat/android/mesh/PowerManager.kt b/app/src/main/java/com/bitchat/android/mesh/PowerManager.kt
index 52b3f5ec..9db444e6 100644
--- a/app/src/main/java/com/bitchat/android/mesh/PowerManager.kt
+++ b/app/src/main/java/com/bitchat/android/mesh/PowerManager.kt
@@ -21,22 +21,22 @@ class PowerManager(private val context: Context) {
         private const val TAG = "PowerManager"
         
         // Battery thresholds
-        private val CRITICAL_BATTERY = com.bitchat.android.util.AppConstants.Power.CRITICAL_BATTERY_PERCENT
-        private val LOW_BATTERY = com.bitchat.android.util.AppConstants.Power.LOW_BATTERY_PERCENT
-        private val MEDIUM_BATTERY = com.bitchat.android.util.AppConstants.Power.MEDIUM_BATTERY_PERCENT
+        private const val CRITICAL_BATTERY = com.bitchat.android.util.AppConstants.Power.CRITICAL_BATTERY_PERCENT
+        private const val LOW_BATTERY = com.bitchat.android.util.AppConstants.Power.LOW_BATTERY_PERCENT
+        private const val MEDIUM_BATTERY = com.bitchat.android.util.AppConstants.Power.MEDIUM_BATTERY_PERCENT
         
         // Scan duty cycle periods (ms)
-        private val SCAN_ON_DURATION_NORMAL = com.bitchat.android.util.AppConstants.Power.SCAN_ON_DURATION_NORMAL_MS    // 8 seconds on
-        private val SCAN_OFF_DURATION_NORMAL = com.bitchat.android.util.AppConstants.Power.SCAN_OFF_DURATION_NORMAL_MS   // 2 seconds off
-        private val SCAN_ON_DURATION_POWER_SAVE = com.bitchat.android.util.AppConstants.Power.SCAN_ON_DURATION_POWER_SAVE_MS    // 2 seconds on
-        private val SCAN_OFF_DURATION_POWER_SAVE = com.bitchat.android.util.AppConstants.Power.SCAN_OFF_DURATION_POWER_SAVE_MS  // 8 seconds off
-        private val SCAN_ON_DURATION_ULTRA_LOW = com.bitchat.android.util.AppConstants.Power.SCAN_ON_DURATION_ULTRA_LOW_MS      // 1 second on
-        private val SCAN_OFF_DURATION_ULTRA_LOW = com.bitchat.android.util.AppConstants.Power.SCAN_OFF_DURATION_ULTRA_LOW_MS   // 10 seconds off
+        private const val SCAN_ON_DURATION_NORMAL = com.bitchat.android.util.AppConstants.Power.SCAN_ON_DURATION_NORMAL_MS    // 8 seconds on
+        private const val SCAN_OFF_DURATION_NORMAL = com.bitchat.android.util.AppConstants.Power.SCAN_OFF_DURATION_NORMAL_MS   // 2 seconds off
+        private const val SCAN_ON_DURATION_POWER_SAVE = com.bitchat.android.util.AppConstants.Power.SCAN_ON_DURATION_POWER_SAVE_MS    // 2 seconds on
+        private const val SCAN_OFF_DURATION_POWER_SAVE = com.bitchat.android.util.AppConstants.Power.SCAN_OFF_DURATION_POWER_SAVE_MS  // 8 seconds off
+        private const val SCAN_ON_DURATION_ULTRA_LOW = com.bitchat.android.util.AppConstants.Power.SCAN_ON_DURATION_ULTRA_LOW_MS      // 1 second on
+        private const val SCAN_OFF_DURATION_ULTRA_LOW = com.bitchat.android.util.AppConstants.Power.SCAN_OFF_DURATION_ULTRA_LOW_MS   // 10 seconds off
         
         // Connection limits
-        private val MAX_CONNECTIONS_NORMAL = com.bitchat.android.util.AppConstants.Power.MAX_CONNECTIONS_NORMAL
-        private val MAX_CONNECTIONS_POWER_SAVE = com.bitchat.android.util.AppConstants.Power.MAX_CONNECTIONS_POWER_SAVE
-        private val MAX_CONNECTIONS_ULTRA_LOW = com.bitchat.android.util.AppConstants.Power.MAX_CONNECTIONS_ULTRA_LOW
+        private const val MAX_CONNECTIONS_NORMAL = com.bitchat.android.util.AppConstants.Power.MAX_CONNECTIONS_NORMAL
+        private const val MAX_CONNECTIONS_POWER_SAVE = com.bitchat.android.util.AppConstants.Power.MAX_CONNECTIONS_POWER_SAVE
+        private const val MAX_CONNECTIONS_ULTRA_LOW = com.bitchat.android.util.AppConstants.Power.MAX_CONNECTIONS_ULTRA_LOW
     }
     
     enum class PowerMode {
diff --git a/app/src/main/java/com/bitchat/android/mesh/SecurityManager.kt b/app/src/main/java/com/bitchat/android/mesh/SecurityManager.kt
index c6c4b90e..476ead73 100644
--- a/app/src/main/java/com/bitchat/android/mesh/SecurityManager.kt
+++ b/app/src/main/java/com/bitchat/android/mesh/SecurityManager.kt
@@ -19,10 +19,10 @@ class SecurityManager(private val encryptionService: EncryptionService, private
     
     companion object {
         private const val TAG = "SecurityManager"
-        private val MESSAGE_TIMEOUT = com.bitchat.android.util.AppConstants.Security.MESSAGE_TIMEOUT_MS // 5 minutes (same as iOS)
-        private val CLEANUP_INTERVAL = com.bitchat.android.util.AppConstants.Security.CLEANUP_INTERVAL_MS // 5 minutes
-        private val MAX_PROCESSED_MESSAGES = com.bitchat.android.util.AppConstants.Security.MAX_PROCESSED_MESSAGES
-        private val MAX_PROCESSED_KEY_EXCHANGES = com.bitchat.android.util.AppConstants.Security.MAX_PROCESSED_KEY_EXCHANGES
+        private const val MESSAGE_TIMEOUT = com.bitchat.android.util.AppConstants.Security.MESSAGE_TIMEOUT_MS // 5 minutes (same as iOS)
+        private const val CLEANUP_INTERVAL = com.bitchat.android.util.AppConstants.Security.CLEANUP_INTERVAL_MS // 5 minutes
+        private const val MAX_PROCESSED_MESSAGES = com.bitchat.android.util.AppConstants.Security.MAX_PROCESSED_MESSAGES
+        private const val MAX_PROCESSED_KEY_EXCHANGES = com.bitchat.android.util.AppConstants.Security.MAX_PROCESSED_KEY_EXCHANGES
     }
     
     // Security tracking
diff --git a/app/src/main/java/com/bitchat/android/mesh/StoreForwardManager.kt b/app/src/main/java/com/bitchat/android/mesh/StoreForwardManager.kt
index cf2e608f..d9dd18d0 100644
--- a/app/src/main/java/com/bitchat/android/mesh/StoreForwardManager.kt
+++ b/app/src/main/java/com/bitchat/android/mesh/StoreForwardManager.kt
@@ -16,10 +16,10 @@ class StoreForwardManager {
     
     companion object {
         private const val TAG = "StoreForwardManager"
-        private val MESSAGE_CACHE_TIMEOUT = com.bitchat.android.util.AppConstants.StoreForward.MESSAGE_CACHE_TIMEOUT_MS  // 12 hours for regular peers
-        private val MAX_CACHED_MESSAGES = com.bitchat.android.util.AppConstants.StoreForward.MAX_CACHED_MESSAGES  // For regular peers
-        private val MAX_CACHED_MESSAGES_FAVORITES = com.bitchat.android.util.AppConstants.StoreForward.MAX_CACHED_MESSAGES_FAVORITES  // For favorites
-        private val CLEANUP_INTERVAL = com.bitchat.android.util.AppConstants.StoreForward.CLEANUP_INTERVAL_MS // 10 minutes
+        private const val MESSAGE_CACHE_TIMEOUT = com.bitchat.android.util.AppConstants.StoreForward.MESSAGE_CACHE_TIMEOUT_MS  // 12 hours for regular peers
+        private const val MAX_CACHED_MESSAGES = com.bitchat.android.util.AppConstants.StoreForward.MAX_CACHED_MESSAGES  // For regular peers
+        private const val MAX_CACHED_MESSAGES_FAVORITES = com.bitchat.android.util.AppConstants.StoreForward.MAX_CACHED_MESSAGES_FAVORITES  // For favorites
+        private const val CLEANUP_INTERVAL = com.bitchat.android.util.AppConstants.StoreForward.CLEANUP_INTERVAL_MS // 10 minutes
     }
     
     /**
diff --git a/app/src/main/java/com/bitchat/android/net/TorManager.kt b/app/src/main/java/com/bitchat/android/net/TorManager.kt
index 3fea1f5b..b7c2230d 100644
--- a/app/src/main/java/com/bitchat/android/net/TorManager.kt
+++ b/app/src/main/java/com/bitchat/android/net/TorManager.kt
@@ -29,11 +29,11 @@ import java.util.concurrent.atomic.AtomicLong
  */
 object TorManager {
     private const val TAG = "TorManager"
-    private val DEFAULT_SOCKS_PORT = com.bitchat.android.util.AppConstants.Tor.DEFAULT_SOCKS_PORT
-    private val RESTART_DELAY_MS = com.bitchat.android.util.AppConstants.Tor.RESTART_DELAY_MS // 2 seconds between stop/start
-    private val INACTIVITY_TIMEOUT_MS = com.bitchat.android.util.AppConstants.Tor.INACTIVITY_TIMEOUT_MS // 5 seconds of no activity before restart
-    private val MAX_RETRY_ATTEMPTS = com.bitchat.android.util.AppConstants.Tor.MAX_RETRY_ATTEMPTS
-    private val STOP_TIMEOUT_MS = com.bitchat.android.util.AppConstants.Tor.STOP_TIMEOUT_MS
+    private const val DEFAULT_SOCKS_PORT = com.bitchat.android.util.AppConstants.Tor.DEFAULT_SOCKS_PORT
+    private const val RESTART_DELAY_MS = com.bitchat.android.util.AppConstants.Tor.RESTART_DELAY_MS // 2 seconds between stop/start
+    private const val INACTIVITY_TIMEOUT_MS = com.bitchat.android.util.AppConstants.Tor.INACTIVITY_TIMEOUT_MS // 5 seconds of no activity before restart
+    private const val MAX_RETRY_ATTEMPTS = com.bitchat.android.util.AppConstants.Tor.MAX_RETRY_ATTEMPTS
+    private const val STOP_TIMEOUT_MS = com.bitchat.android.util.AppConstants.Tor.STOP_TIMEOUT_MS
 
     private val appScope = CoroutineScope(Dispatchers.IO + SupervisorJob())
 
diff --git a/app/src/main/java/com/bitchat/android/noise/NoiseEncryptionService.kt b/app/src/main/java/com/bitchat/android/noise/NoiseEncryptionService.kt
index b6051a06..f9e969d3 100644
--- a/app/src/main/java/com/bitchat/android/noise/NoiseEncryptionService.kt
+++ b/app/src/main/java/com/bitchat/android/noise/NoiseEncryptionService.kt
@@ -24,8 +24,8 @@ class NoiseEncryptionService(private val context: Context) {
         private const val TAG = "NoiseEncryptionService"
         
         // Session limits for performance and security
-        private val REKEY_TIME_LIMIT = com.bitchat.android.util.AppConstants.Noise.REKEY_TIME_LIMIT_MS // 1 hour (same as iOS)
-        private val REKEY_MESSAGE_LIMIT = com.bitchat.android.util.AppConstants.Noise.REKEY_MESSAGE_LIMIT_ENCRYPTION // 1k messages (matches iOS) (same as iOS)
+        private const val REKEY_TIME_LIMIT = com.bitchat.android.util.AppConstants.Noise.REKEY_TIME_LIMIT_MS // 1 hour (same as iOS)
+        private const val REKEY_MESSAGE_LIMIT = com.bitchat.android.util.AppConstants.Noise.REKEY_MESSAGE_LIMIT_ENCRYPTION // 1k messages (matches iOS) (same as iOS)
     }
     
     // Static identity key (persistent across app restarts) - loaded from secure storage
diff --git a/app/src/main/java/com/bitchat/android/noise/NoiseSession.kt b/app/src/main/java/com/bitchat/android/noise/NoiseSession.kt
index 06dfe54d..dc4a3d50 100644
--- a/app/src/main/java/com/bitchat/android/noise/NoiseSession.kt
+++ b/app/src/main/java/com/bitchat/android/noise/NoiseSession.kt
@@ -25,8 +25,8 @@ class NoiseSession(
         private const val PROTOCOL_NAME = "Noise_XX_25519_ChaChaPoly_SHA256"
         
         // Rekey thresholds (same as iOS)
-        private val REKEY_TIME_LIMIT = com.bitchat.android.util.AppConstants.Noise.REKEY_TIME_LIMIT_MS // 1 hour
-        private val REKEY_MESSAGE_LIMIT = com.bitchat.android.util.AppConstants.Noise.REKEY_MESSAGE_LIMIT_SESSION // 10k messages
+        private const val REKEY_TIME_LIMIT = com.bitchat.android.util.AppConstants.Noise.REKEY_TIME_LIMIT_MS // 1 hour
+        private const val REKEY_MESSAGE_LIMIT = com.bitchat.android.util.AppConstants.Noise.REKEY_MESSAGE_LIMIT_SESSION // 10k messages
         
         // XX Pattern Message Sizes (exactly matching iOS implementation)
         private const val XX_MESSAGE_1_SIZE = 32      // -> e (ephemeral key only)
@@ -34,13 +34,13 @@ class NoiseSession(
         private const val XX_MESSAGE_3_SIZE = 48      // -> s, se (encrypted static key)
         
         // Maximum payload size for safety
-        private val MAX_PAYLOAD_SIZE = com.bitchat.android.util.AppConstants.Noise.MAX_PAYLOAD_SIZE_BYTES
+        private const val MAX_PAYLOAD_SIZE = com.bitchat.android.util.AppConstants.Noise.MAX_PAYLOAD_SIZE_BYTES
         
         // Constants for replay protection (matching iOS implementation)
         private const val NONCE_SIZE_BYTES = 4
         private const val REPLAY_WINDOW_SIZE = 1024
         private const val REPLAY_WINDOW_BYTES = REPLAY_WINDOW_SIZE / 8 // 128 bytes
-        private val HIGH_NONCE_WARNING_THRESHOLD = com.bitchat.android.util.AppConstants.Noise.HIGH_NONCE_WARNING_THRESHOLD
+        private const val HIGH_NONCE_WARNING_THRESHOLD = com.bitchat.android.util.AppConstants.Noise.HIGH_NONCE_WARNING_THRESHOLD
         
         // MARK: - Sliding Window Replay Protection
         
diff --git a/app/src/main/java/com/bitchat/android/nostr/NostrEventDeduplicator.kt b/app/src/main/java/com/bitchat/android/nostr/NostrEventDeduplicator.kt
index 81b53bbe..0638eafd 100644
--- a/app/src/main/java/com/bitchat/android/nostr/NostrEventDeduplicator.kt
+++ b/app/src/main/java/com/bitchat/android/nostr/NostrEventDeduplicator.kt
@@ -22,7 +22,7 @@ class NostrEventDeduplicator(
 ) {
     companion object {
         private const val TAG = "NostrDeduplicator"
-        private val DEFAULT_CAPACITY = com.bitchat.android.util.AppConstants.Nostr.DEFAULT_DEDUP_CAPACITY
+        private const val DEFAULT_CAPACITY = com.bitchat.android.util.AppConstants.Nostr.DEFAULT_DEDUP_CAPACITY
         
         @Volatile
         private var INSTANCE: NostrEventDeduplicator? = null
diff --git a/app/src/main/java/com/bitchat/android/nostr/NostrRelayManager.kt b/app/src/main/java/com/bitchat/android/nostr/NostrRelayManager.kt
index dfe3253d..eb5806bb 100644
--- a/app/src/main/java/com/bitchat/android/nostr/NostrRelayManager.kt
+++ b/app/src/main/java/com/bitchat/android/nostr/NostrRelayManager.kt
@@ -41,10 +41,10 @@ class NostrRelayManager private constructor() {
         )
         
         // Exponential backoff configuration (same as iOS)
-        private val INITIAL_BACKOFF_INTERVAL = com.bitchat.android.util.AppConstants.Nostr.INITIAL_BACKOFF_INTERVAL_MS  // 1 second
-        private val MAX_BACKOFF_INTERVAL = com.bitchat.android.util.AppConstants.Nostr.MAX_BACKOFF_INTERVAL_MS    // 5 minutes
-        private val BACKOFF_MULTIPLIER = com.bitchat.android.util.AppConstants.Nostr.BACKOFF_MULTIPLIER
-        private val MAX_RECONNECT_ATTEMPTS = com.bitchat.android.util.AppConstants.Nostr.MAX_RECONNECT_ATTEMPTS
+        private const val INITIAL_BACKOFF_INTERVAL = com.bitchat.android.util.AppConstants.Nostr.INITIAL_BACKOFF_INTERVAL_MS  // 1 second
+        private const val MAX_BACKOFF_INTERVAL = com.bitchat.android.util.AppConstants.Nostr.MAX_BACKOFF_INTERVAL_MS    // 5 minutes
+        private const val BACKOFF_MULTIPLIER = com.bitchat.android.util.AppConstants.Nostr.BACKOFF_MULTIPLIER
+        private const val MAX_RECONNECT_ATTEMPTS = com.bitchat.android.util.AppConstants.Nostr.MAX_RECONNECT_ATTEMPTS
         
         // Track gift-wraps we initiated for logging
         private val pendingGiftWrapIDs = ConcurrentHashMap.newKeySet<String>()
diff --git a/app/src/main/java/com/bitchat/android/nostr/NostrTransport.kt b/app/src/main/java/com/bitchat/android/nostr/NostrTransport.kt
index a9179c01..26ba8369 100644
--- a/app/src/main/java/com/bitchat/android/nostr/NostrTransport.kt
+++ b/app/src/main/java/com/bitchat/android/nostr/NostrTransport.kt
@@ -19,7 +19,7 @@ class NostrTransport(
     
     companion object {
         private const val TAG = "NostrTransport"
-        private val READ_ACK_INTERVAL = com.bitchat.android.util.AppConstants.Nostr.READ_ACK_INTERVAL_MS // ~3 per second (0.35s interval like iOS)
+        private const val READ_ACK_INTERVAL = com.bitchat.android.util.AppConstants.Nostr.READ_ACK_INTERVAL_MS // ~3 per second (0.35s interval like iOS)
         
         @Volatile
         private var INSTANCE: NostrTransport? = null
diff --git a/app/src/main/java/com/bitchat/android/protocol/CompressionUtil.kt b/app/src/main/java/com/bitchat/android/protocol/CompressionUtil.kt
index cdc3e2d4..e8b59254 100644
--- a/app/src/main/java/com/bitchat/android/protocol/CompressionUtil.kt
+++ b/app/src/main/java/com/bitchat/android/protocol/CompressionUtil.kt
@@ -10,7 +10,7 @@ import java.util.zip.Inflater
  * Uses the same zlib algorithm as iOS CompressionUtil.swift
  */
 object CompressionUtil {
-    private val COMPRESSION_THRESHOLD = com.bitchat.android.util.AppConstants.Protocol.COMPRESSION_THRESHOLD_BYTES  // bytes - same as iOS
+    private const val COMPRESSION_THRESHOLD = com.bitchat.android.util.AppConstants.Protocol.COMPRESSION_THRESHOLD_BYTES  // bytes - same as iOS
     
     /**
      * Helper to check if compression is worth it - exact same logic as iOS
diff --git a/app/src/main/java/com/bitchat/android/services/SeenMessageStore.kt b/app/src/main/java/com/bitchat/android/services/SeenMessageStore.kt
index 4354f0e3..a6cd2378 100644
--- a/app/src/main/java/com/bitchat/android/services/SeenMessageStore.kt
+++ b/app/src/main/java/com/bitchat/android/services/SeenMessageStore.kt
@@ -13,7 +13,7 @@ class SeenMessageStore private constructor(private val context: Context) {
     companion object {
         private const val TAG = "SeenMessageStore"
         private const val STORAGE_KEY = "seen_message_store_v1"
-        private val MAX_IDS = com.bitchat.android.util.AppConstants.Services.SEEN_MESSAGE_MAX_IDS
+        private const val MAX_IDS = com.bitchat.android.util.AppConstants.Services.SEEN_MESSAGE_MAX_IDS
 
         @Volatile private var INSTANCE: SeenMessageStore? = null
         fun getInstance(appContext: Context): SeenMessageStore {
diff --git a/app/src/main/java/com/bitchat/android/sync/GossipSyncManager.kt b/app/src/main/java/com/bitchat/android/sync/GossipSyncManager.kt
index 46eee7ce..6e29aa79 100644
--- a/app/src/main/java/com/bitchat/android/sync/GossipSyncManager.kt
+++ b/app/src/main/java/com/bitchat/android/sync/GossipSyncManager.kt
@@ -117,8 +117,8 @@ class GossipSyncManager(
             // Ignore stale announcements older than STALE_PEER_TIMEOUT
             val now = System.currentTimeMillis()
             val age = now - packet.timestamp.toLong()
-            if (age > com.bitchat.android.util.AppConstants.STALE_PEER_TIMEOUT_MS) {
-                Log.d(TAG, "Ignoring stale ANNOUNCE (age=${age}ms > ${com.bitchat.android.util.AppConstants.STALE_PEER_TIMEOUT_MS}ms)")
+            if (age > com.bitchat.android.util.AppConstants.Mesh.STALE_PEER_TIMEOUT_MS) {
+                Log.d(TAG, "Ignoring stale ANNOUNCE (age=${age}ms > ${com.bitchat.android.util.AppConstants.Mesh.STALE_PEER_TIMEOUT_MS}ms)")
                 return
             }
             // senderID is fixed-size 8 bytes; map to hex string for key
@@ -267,7 +267,7 @@ class GossipSyncManager(
         for ((peerID, pair) in latestAnnouncementByPeer.entries) {
             val pkt = pair.second
             val age = now - pkt.timestamp.toLong()
-            if (age > com.bitchat.android.util.AppConstants.STALE_PEER_TIMEOUT_MS) {
+            if (age > com.bitchat.android.util.AppConstants.Mesh.STALE_PEER_TIMEOUT_MS) {
                 stalePeers.add(peerID)
             }
         }
diff --git a/app/src/main/java/com/bitchat/android/ui/MediaSendingManager.kt b/app/src/main/java/com/bitchat/android/ui/MediaSendingManager.kt
index 63611d0a..0a6be528 100644
--- a/app/src/main/java/com/bitchat/android/ui/MediaSendingManager.kt
+++ b/app/src/main/java/com/bitchat/android/ui/MediaSendingManager.kt
@@ -20,7 +20,7 @@ class MediaSendingManager(
 ) {
     companion object {
         private const val TAG = "MediaSendingManager"
-        private val MAX_FILE_SIZE = com.bitchat.android.util.AppConstants.Media.MAX_FILE_SIZE_BYTES // 50MB limit
+        private const val MAX_FILE_SIZE = com.bitchat.android.util.AppConstants.Media.MAX_FILE_SIZE_BYTES // 50MB limit
     }
 
     // Track in-flight transfer progress: transferId -> messageId and reverse
diff --git a/app/src/main/java/com/bitchat/android/ui/NotificationManager.kt b/app/src/main/java/com/bitchat/android/ui/NotificationManager.kt
index 380108b6..622800ca 100644
--- a/app/src/main/java/com/bitchat/android/ui/NotificationManager.kt
+++ b/app/src/main/java/com/bitchat/android/ui/NotificationManager.kt
@@ -42,7 +42,7 @@ class NotificationManager(
         private const val SUMMARY_NOTIFICATION_ID = 999
       private const val GEOHASH_SUMMARY_NOTIFICATION_ID = 998
         private const val ACTIVE_PEERS_NOTIFICATION_ID = 997
-        private val ACTIVE_PEERS_NOTIFICATION_TIME_INTERVAL = com.bitchat.android.util.AppConstants.UI.ACTIVE_PEERS_NOTIFICATION_INTERVAL_MS
+        private const val ACTIVE_PEERS_NOTIFICATION_TIME_INTERVAL = com.bitchat.android.util.AppConstants.UI.ACTIVE_PEERS_NOTIFICATION_INTERVAL_MS
 
         // Intent extras for notification handling
         const val EXTRA_OPEN_PRIVATE_CHAT = "open_private_chat"
diff --git a/app/src/main/java/com/bitchat/android/ui/theme/Typography.kt b/app/src/main/java/com/bitchat/android/ui/theme/Typography.kt
index 52b5bd6b..a8c68a4b 100644
--- a/app/src/main/java/com/bitchat/android/ui/theme/Typography.kt
+++ b/app/src/main/java/com/bitchat/android/ui/theme/Typography.kt
@@ -7,7 +7,7 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.sp
 
 // Base font size for consistent scaling across the app
-private val BASE_FONT_SIZE = com.bitchat.android.util.AppConstants.UI.BASE_FONT_SIZE_SP // sp - increased from 14sp for better readability
+internal const val BASE_FONT_SIZE = com.bitchat.android.util.AppConstants.UI.BASE_FONT_SIZE_SP // sp - increased from 14sp for better readability
 
 // Typography matching the iOS monospace design - using BASE_FONT_SIZE for consistency
 val Typography = Typography(