diff --git a/src/nostr/client.py b/src/nostr/client.py
index 59da02f..7af1a0e 100644
--- a/src/nostr/client.py
+++ b/src/nostr/client.py
@@ -73,7 +73,11 @@ class NostrClient:
 
     def initialize_client_pool(self) -> None:
         """Add relays to the client and connect."""
-        self.client.add_relays(self.relays)
+        if hasattr(self.client, "add_relays"):
+            self.client.add_relays(self.relays)
+        else:
+            for relay in self.relays:
+                self.client.add_relay(relay)
         self.client.connect()
         logger.info(f"NostrClient connected to relays: {self.relays}")
 
diff --git a/src/tests/test_nostr_client.py b/src/tests/test_nostr_client.py
index 7daac71..75a0ecc 100644
--- a/src/tests/test_nostr_client.py
+++ b/src/tests/test_nostr_client.py
@@ -24,3 +24,54 @@ def test_nostr_client_uses_custom_relays():
                 client = NostrClient(enc_mgr, "fp", relays=custom_relays)
 
         assert client.relays == custom_relays
+
+
+class FakeAddRelaysClient:
+    def __init__(self, _signer):
+        self.added = []
+        self.connected = False
+
+    def add_relays(self, relays):
+        self.added.append(relays)
+
+    def connect(self):
+        self.connected = True
+
+
+class FakeAddRelayClient:
+    def __init__(self, _signer):
+        self.added = []
+        self.connected = False
+
+    def add_relay(self, relay):
+        self.added.append(relay)
+
+    def connect(self):
+        self.connected = True
+
+
+def _setup_client(tmpdir, fake_cls):
+    key = Fernet.generate_key()
+    enc_mgr = EncryptionManager(key, Path(tmpdir))
+
+    with patch("nostr.client.Client", fake_cls), patch(
+        "nostr.client.KeyManager"
+    ) as MockKM, patch.object(enc_mgr, "decrypt_parent_seed", return_value="seed"):
+        km_inst = MockKM.return_value
+        km_inst.keys.private_key_hex.return_value = "1" * 64
+        client = NostrClient(enc_mgr, "fp")
+    return client
+
+
+def test_initialize_client_pool_add_relays_used(tmp_path):
+    client = _setup_client(tmp_path, FakeAddRelaysClient)
+    fc = client.client
+    assert fc.added == [client.relays]
+    assert fc.connected is True
+
+
+def test_initialize_client_pool_add_relay_fallback(tmp_path):
+    client = _setup_client(tmp_path, FakeAddRelayClient)
+    fc = client.client
+    assert fc.added == client.relays
+    assert fc.connected is True