diff --git a/irctest/server_tests/cap.py b/irctest/server_tests/cap.py
index 05892897..8cc8258d 100644
--- a/irctest/server_tests/cap.py
+++ b/irctest/server_tests/cap.py
@@ -20,7 +20,7 @@ def testInvalidCapSubcommand(self):
         m = self.getRegistrationMessage(1)
         self.assertTrue(
             self.messageDiffers(m, command="PONG", params=[ANYSTR, "test123"]),
-            "Sending “CAP NOTACOMMAND” as first message got no reply"
+            "Sending “CAP NOTACOMMAND” as first message got no reply",
         )
         self.assertMessageMatch(
             m,
@@ -56,18 +56,24 @@ def testNoReq(self):
         )
 
     @cases.mark_specifications("IRCv3")
+    @cases.xfailIfSoftware(
+        ["UnrealIRCd"],
+        "UnrealIRCd sends a trailing space on CAP ACK: https://github.com/unrealircd/unrealircd/pull/148",
+    )
     def testReqOne(self):
         """Tests requesting a single capability"""
         self.addClient(1)
-        self.sendLine(1, "CAP LS 302")
+        self.sendLine(1, "CAP LS")
         self.getCapLs(1)
         self.sendLine(1, "USER foo foo foo :foo")
         self.sendLine(1, "NICK foo")
-        self.sendLine(1, "CAP REQ :server-time")
+        self.sendLine(1, "CAP REQ :multi-prefix")
         m = self.getRegistrationMessage(1)
         self.assertMessageMatch(
-            m, command="CAP", params=[ANYSTR, "ACK", "server-time"],
-            fail_msg="Expected CAP ACK after sending CAP REQ, got {msg}."
+            m,
+            command="CAP",
+            params=[ANYSTR, "ACK", "multi-prefix"],
+            fail_msg="Expected CAP ACK after sending CAP REQ, got {msg}.",
         )
 
         self.sendLine(1, "CAP LIST")
@@ -75,8 +81,8 @@ def testReqOne(self):
         self.assertMessageMatch(
             m,
             command="CAP",
-            params=[ANYSTR, "LIST", "server-time"],
-        fail_msg="Expected CAP LIST after sending CAP LIST, got {msg}."
+            params=[ANYSTR, "LIST", "multi-prefix"],
+            fail_msg="Expected CAP LIST after sending CAP LIST, got {msg}.",
         )
 
         self.sendLine(1, "CAP END")
@@ -86,18 +92,24 @@ def testReqOne(self):
         )
 
     @cases.mark_specifications("IRCv3")
+    @cases.xfailIfSoftware(
+        ["UnrealIRCd"],
+        "UnrealIRCd sends a trailing space on CAP ACK: https://github.com/unrealircd/unrealircd/pull/148",
+    )
     def testReqTwo(self):
         """Tests requesting two capabilities at once"""
         self.addClient(1)
-        self.sendLine(1, "CAP LS 302")
+        self.sendLine(1, "CAP LS")
         self.getCapLs(1)
         self.sendLine(1, "USER foo foo foo :foo")
         self.sendLine(1, "NICK foo")
-        self.sendLine(1, "CAP REQ :server-time userhost-in-names")
+        self.sendLine(1, "CAP REQ :multi-prefix userhost-in-names")
         m = self.getRegistrationMessage(1)
         self.assertMessageMatch(
-            m, command="CAP", params=[ANYSTR, "ACK", "server-time userhost-in-names"],
-            fail_msg="Expected CAP ACK after sending CAP REQ, got {msg}."
+            m,
+            command="CAP",
+            params=[ANYSTR, "ACK", "multi-prefix userhost-in-names"],
+            fail_msg="Expected CAP ACK after sending CAP REQ, got {msg}.",
         )
 
         self.sendLine(1, "CAP LIST")
@@ -105,8 +117,8 @@ def testReqTwo(self):
         self.assertMessageMatch(
             m,
             command="CAP",
-            params=[ANYSTR, "LIST", "server-time userhost-in-names"],
-            fail_msg="Expected CAP LIST after sending CAP LIST, got {msg}."
+            params=[ANYSTR, "LIST", "multi-prefix userhost-in-names"],
+            fail_msg="Expected CAP LIST after sending CAP LIST, got {msg}.",
         )
 
         self.sendLine(1, "CAP END")
@@ -116,26 +128,34 @@ def testReqTwo(self):
         )
 
     @cases.mark_specifications("IRCv3")
+    @cases.xfailIfSoftware(
+        ["UnrealIRCd"],
+        "UnrealIRCd sends a trailing space on CAP ACK: https://github.com/unrealircd/unrealircd/pull/148",
+    )
     def testReqOneThenOne(self):
         """Tests requesting two capabilities in different messages"""
         self.addClient(1)
-        self.sendLine(1, "CAP LS 302")
+        self.sendLine(1, "CAP LS")
         self.getCapLs(1)
         self.sendLine(1, "USER foo foo foo :foo")
         self.sendLine(1, "NICK foo")
 
-        self.sendLine(1, "CAP REQ :server-time")
+        self.sendLine(1, "CAP REQ :multi-prefix")
         m = self.getRegistrationMessage(1)
         self.assertMessageMatch(
-            m, command="CAP", params=[ANYSTR, "ACK", "server-time"],
-            fail_msg="Expected CAP ACK after sending CAP REQ, got {msg}."
+            m,
+            command="CAP",
+            params=[ANYSTR, "ACK", "multi-prefix"],
+            fail_msg="Expected CAP ACK after sending CAP REQ, got {msg}.",
         )
 
         self.sendLine(1, "CAP REQ :userhost-in-names")
         m = self.getRegistrationMessage(1)
         self.assertMessageMatch(
-            m, command="CAP", params=[ANYSTR, "ACK", "userhost-in-names"],
-            fail_msg="Expected CAP ACK after sending CAP REQ, got {msg}."
+            m,
+            command="CAP",
+            params=[ANYSTR, "ACK", "userhost-in-names"],
+            fail_msg="Expected CAP ACK after sending CAP REQ, got {msg}.",
         )
 
         self.sendLine(1, "CAP LIST")
@@ -143,8 +163,8 @@ def testReqOneThenOne(self):
         self.assertMessageMatch(
             m,
             command="CAP",
-            params=[ANYSTR, "LIST", "server-time userhost-in-names"],
-            fail_msg="Expected CAP LIST after sending CAP LIST, got {msg}."
+            params=[ANYSTR, "LIST", "multi-prefix userhost-in-names"],
+            fail_msg="Expected CAP LIST after sending CAP LIST, got {msg}.",
         )
 
         self.sendLine(1, "CAP END")
@@ -154,19 +174,25 @@ def testReqOneThenOne(self):
         )
 
     @cases.mark_specifications("IRCv3")
+    @cases.xfailIfSoftware(
+        ["UnrealIRCd"],
+        "UnrealIRCd sends a trailing space on CAP ACK: https://github.com/unrealircd/unrealircd/pull/148",
+    )
     def testReqPostRegistration(self):
         """Tests requesting more capabilities after CAP END"""
         self.addClient(1)
-        self.sendLine(1, "CAP LS 302")
+        self.sendLine(1, "CAP LS")
         self.getCapLs(1)
         self.sendLine(1, "USER foo foo foo :foo")
         self.sendLine(1, "NICK foo")
 
-        self.sendLine(1, "CAP REQ :server-time")
+        self.sendLine(1, "CAP REQ :multi-prefix")
         m = self.getRegistrationMessage(1)
         self.assertMessageMatch(
-            m, command="CAP", params=[ANYSTR, "ACK", "server-time"],
-            fail_msg="Expected CAP ACK after sending CAP REQ, got {msg}."
+            m,
+            command="CAP",
+            params=[ANYSTR, "ACK", "multi-prefix"],
+            fail_msg="Expected CAP ACK after sending CAP REQ, got {msg}.",
         )
 
         self.sendLine(1, "CAP LIST")
@@ -175,7 +201,7 @@ def testReqPostRegistration(self):
             m,
             command="CAP",
             params=[ANYSTR, "LIST", "server-time"],
-            fail_msg="Expected CAP LIST after sending CAP LIST, got {msg}."
+            fail_msg="Expected CAP LIST after sending CAP LIST, got {msg}.",
         )
 
         self.sendLine(1, "CAP END")
@@ -189,8 +215,10 @@ def testReqPostRegistration(self):
         self.sendLine(1, "CAP REQ :userhost-in-names")
         m = self.getRegistrationMessage(1)
         self.assertMessageMatch(
-            m, command="CAP", params=[ANYSTR, "ACK", "userhost-in-names"],
-            fail_msg="Expected CAP ACK after sending CAP REQ, got {msg}."
+            m,
+            command="CAP",
+            params=[ANYSTR, "ACK", "userhost-in-names"],
+            fail_msg="Expected CAP ACK after sending CAP REQ, got {msg}.",
         )
 
         self.sendLine(1, "CAP LIST")
@@ -199,7 +227,7 @@ def testReqPostRegistration(self):
             m,
             command="CAP",
             params=[ANYSTR, "LIST", "server-time userhost-in-names"],
-            fail_msg="Expected CAP LIST after sending CAP LIST, got {msg}."
+            fail_msg="Expected CAP LIST after sending CAP LIST, got {msg}.",
         )
 
     @cases.mark_specifications("IRCv3")