diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/client/ClientsFragment.kt b/mobile/src/main/java/be/mygod/vpnhotspot/client/ClientsFragment.kt
index cd6a51d9..11271be7 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/client/ClientsFragment.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/client/ClientsFragment.kt
@@ -210,7 +210,7 @@ class ClientsFragment : Fragment() {
 
     private lateinit var binding: FragmentClientsBinding
     private val adapter = ClientAdapter()
-    private var rates = HashMap<Pair<String, Long>, TrafficRate>()
+    private var rates = mutableMapOf<Pair<String, Long>, TrafficRate>()
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
         binding = FragmentClientsBinding.inflate(inflater, container, false)
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/net/Routing.kt b/mobile/src/main/java/be/mygod/vpnhotspot/net/Routing.kt
index 456a23c9..9063030b 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/net/Routing.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/net/Routing.kt
@@ -227,7 +227,7 @@ class Routing(private val caller: Any, private val downstream: String) : IpNeigh
             transaction.revert()
         }
     }
-    private val clients = HashMap<InetAddress, Client>()
+    private val clients = mutableMapOf<InetAddress, Client>()
     override fun onIpNeighbourAvailable(neighbours: Collection<IpNeighbour>) = synchronized(this) {
         val toRemove = HashSet(clients.keys)
         for (neighbour in neighbours) {
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/TrafficRecorder.kt b/mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/TrafficRecorder.kt
index 91c302bd..b21b7909 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/TrafficRecorder.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/TrafficRecorder.kt
@@ -20,7 +20,7 @@ object TrafficRecorder {
 
     private var scheduled = false
     private var lastUpdate = 0L
-    private val records = HashMap<Pair<InetAddress, String>, TrafficRecord>()
+    private val records = mutableMapOf<Pair<InetAddress, String>, TrafficRecord>()
     val foregroundListeners = Event2<Collection<TrafficRecord>, LongSparseArray<TrafficRecord>>()
 
     fun register(ip: InetAddress, downstream: String, mac: Long) {