diff --git a/patches/apply_pymumble_ssl.py b/patches/apply_pymumble_ssl.py
index 2f6b6c3..89b8b5a 100644
--- a/patches/apply_pymumble_ssl.py
+++ b/patches/apply_pymumble_ssl.py
@@ -2,6 +2,7 @@
 
 1. pymumble: ssl.wrap_socket was removed in 3.13
 2. opuslib: ctypes.util.find_library fails on musl-based distros
+3. pymumble: protocol version 1.2.4 is rejected by modern servers
 """
 
 import pathlib
@@ -65,5 +66,29 @@ new_init = """\
         self.control_socket = None"""
 
 assert old_init in src, "pymumble init_connection socket patch target not found"
-p.write_text(src.replace(old_init, new_init))
+src = src.replace(old_init, new_init)
 print("pymumble reconnect socket patch applied")
+
+p.write_text(src)
+
+# -- pymumble: report modern protocol version --
+# PyMumble 1.6.1 reports protocol version 1.2.4, which modern Murmur
+# (1.5.x) treats as an invalid/legacy client.  Update to 1.5.0 so the
+# server enables full feature set and stops sending warnings.
+p = pathlib.Path(f"{site}/pymumble_py3/constants.py")
+src = p.read_text()
+
+old_ver = "PYMUMBLE_PROTOCOL_VERSION = (1, 2, 4)"
+new_ver = "PYMUMBLE_PROTOCOL_VERSION = (1, 5, 0)"
+
+assert old_ver in src, "pymumble version patch target not found"
+src = src.replace(old_ver, new_ver)
+
+old_os = 'PYMUMBLE_OS_STRING = "PyMumble %s" % PYMUMBLE_VERSION'
+new_os = 'PYMUMBLE_OS_STRING = platform.system()'
+
+assert old_os in src, "pymumble OS string patch target not found"
+src = src.replace(old_os, new_os)
+
+p.write_text(src)
+print("pymumble version patch applied (1.5.0, native OS string)")
diff --git a/src/derp/mumble.py b/src/derp/mumble.py
index 3a76e2f..f5d5a3b 100644
--- a/src/derp/mumble.py
+++ b/src/derp/mumble.py
@@ -218,11 +218,27 @@ class MumbleBot:
             self._on_sound_received,
         )
         self._mumble.set_receive_sound(self._receive_sound)
+        # Raise retry interval so 2+ bots on the same IP don't trip
+        # the server's autoban (default: 10 attempts / 120s).
+        import pymumble_py3.mumble as _pm
+        if getattr(_pm, "PYMUMBLE_CONNECTION_RETRY_INTERVAL", 0) < 15:
+            _pm.PYMUMBLE_CONNECTION_RETRY_INTERVAL = 15
         self._mumble.start()
         self._mumble.is_ready()
 
     def _on_connected(self) -> None:
         """Callback from pymumble thread: connection established."""
+        # Enable TCP keepalive on the control socket to prevent NAT
+        # gateways from dropping the mapping during idle periods.
+        try:
+            import socket as _sock
+            raw = self._mumble.control_socket
+            raw.setsockopt(_sock.SOL_SOCKET, _sock.SO_KEEPALIVE, 1)
+            raw.setsockopt(_sock.IPPROTO_TCP, _sock.TCP_KEEPIDLE, 10)
+            raw.setsockopt(_sock.IPPROTO_TCP, _sock.TCP_KEEPINTVL, 5)
+            raw.setsockopt(_sock.IPPROTO_TCP, _sock.TCP_KEEPCNT, 3)
+        except Exception:
+            pass
         self._connect_count += 1
         kind = "reconnected" if self._connect_count > 1 else "connected"
         session = getattr(self._mumble.users, "myself_session", "?")