diff --git a/debian/patches/python-3.9.patch b/debian/patches/python-3.9.patch
new file mode 100644
index 00000000..1535abed
--- /dev/null
+++ b/debian/patches/python-3.9.patch
@@ -0,0 +1,74 @@
+Index: fail2ban/fail2ban/server/jailthread.py
+===================================================================
+--- fail2ban.orig/fail2ban/server/jailthread.py
++++ fail2ban/fail2ban/server/jailthread.py
+@@ -120,3 +120,6 @@ class JailThread(Thread):
+ ## python 2.x replace binding of private __bootstrap method:
+ if sys.version_info < (3,): # pragma: 3.x no cover
+ 	JailThread._Thread__bootstrap = JailThread._JailThread__bootstrap
++## python 3.9, restore isAlive method:
++elif not hasattr(JailThread, 'isAlive'): # pragma: 2.x no cover
++	 JailThread.isAlive = JailThread.is_alive
+Index: fail2ban/fail2ban/tests/sockettestcase.py
+===================================================================
+--- fail2ban.orig/fail2ban/tests/sockettestcase.py
++++ fail2ban/fail2ban/tests/sockettestcase.py
+@@ -83,11 +83,11 @@ class Socket(LogCaptureTestCase):
+ 		serverThread.start()
+ 		self.assertTrue(Utils.wait_for(self.server.isActive, unittest.F2B.maxWaitTime(10)))
+ 		return serverThread
+-	
++
+ 	def _stopServerThread(self):
+ 		serverThread = self.serverThread
+ 		# wait for end of thread :
+-		Utils.wait_for(lambda: not serverThread.isAlive() 
++		Utils.wait_for(lambda: not serverThread.is_alive()
+ 			or serverThread.join(Utils.DEFAULT_SLEEP_TIME), unittest.F2B.maxWaitTime(10))
+ 		self.serverThread = None
+ 
+@@ -98,7 +98,7 @@ class Socket(LogCaptureTestCase):
+ 		self.server.close()
+ 		# wait for end of thread :
+ 		self._stopServerThread()
+-		self.assertFalse(serverThread.isAlive())
++		self.assertFalse(serverThread.is_alive())
+ 		# clean :
+ 		self.server.stop()
+ 		self.assertFalse(self.server.isActive())
+@@ -139,7 +139,7 @@ class Socket(LogCaptureTestCase):
+ 		self.server.stop()
+ 		# wait for end of thread :
+ 		self._stopServerThread()
+-		self.assertFalse(serverThread.isAlive())
++		self.assertFalse(serverThread.is_alive())
+ 		self.assertFalse(self.server.isActive())
+ 		self.assertFalse(os.path.exists(self.sock_name))
+ 
+@@ -149,7 +149,7 @@ class Socket(LogCaptureTestCase):
+ 		client = Utils.wait_for(self._serverSocket, 2)
+ 		# unexpected stop during message body:
+ 		testMessage = ["A", "test", "message", [protocol.CSPROTO.END]]
+-		
++
+ 		org_handler = RequestHandler.found_terminator
+ 		try:
+ 			RequestHandler.found_terminator = lambda self: self.close()
+@@ -180,7 +180,7 @@ class Socket(LogCaptureTestCase):
+ 		self.server.stop()
+ 		# wait for end of thread :
+ 		self._stopServerThread()
+-		self.assertFalse(serverThread.isAlive())
++		self.assertFalse(serverThread.is_alive())
+ 
+ 	def testLoopErrors(self):
+ 		# replace poll handler to produce error in loop-cycle:
+@@ -216,7 +216,7 @@ class Socket(LogCaptureTestCase):
+ 		self.server.stop()
+ 		# wait for end of thread :
+ 		self._stopServerThread()
+-		self.assertFalse(serverThread.isAlive())
++		self.assertFalse(serverThread.is_alive())
+ 		self.assertFalse(self.server.isActive())
+ 		self.assertFalse(os.path.exists(self.sock_name))
+ 
diff --git a/debian/patches/roundcude-update.diff b/debian/patches/roundcude-update.diff
deleted file mode 100644
index 3304d0bc..00000000
--- a/debian/patches/roundcude-update.diff
+++ /dev/null
@@ -1,11 +0,0 @@
---- fail2ban-0.11.1.orig/config/filter.d/roundcube-auth.conf
-+++ fail2ban-0.11.1/config/filter.d/roundcube-auth.conf
-@@ -18,7 +18,7 @@ prefregex = ^\s*(\[\])?(%(__hostname)s\s
- failregex = ^(?:FAILED login|Login failed) for <F-USER>.*</F-USER> from <HOST>(?:(?:\([^\)]*\))?\. (?:(?! from ).)*(?: user=(?P=user))? in \S+\.php on line \d+ \(\S+ \S+\))?$
-             ^(?:<[\w]+> )?Failed login for <F-USER>.*</F-USER> from <HOST> in session \w+( \(error: \d\))?$
- 
--ignoreregex = 
-+ignoreregex = Could not connect to .* Connection refused
- 
- journalmatch = SYSLOG_IDENTIFIER=roundcube
- 
diff --git a/debian/patches/series b/debian/patches/series
index 4fbf4140..6fb515d1 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -5,4 +5,4 @@ deb_manpages_reportbug
 deb_no_iptables_service
 python3-test-suite.diff
 no-python-user.diff
-roundcude-update.diff
+python-3.9.patch