diff --git a/roles/xmpp_server/molecule/default/molecule.yml b/roles/xmpp_server/molecule/default/molecule.yml
index b800f059efef57644141854c4884723ffd9a4093..058d724fa79b3d451f36d54f211fe8beaf44eea2 100644
--- a/roles/xmpp_server/molecule/default/molecule.yml
+++ b/roles/xmpp_server/molecule/default/molecule.yml
@@ -38,7 +38,11 @@ platforms:
     groups:
       - clients
       - bullseye
-    box: debian/bullseye64
+    # Use Bookworm client box for testing Bullseye servers to avoid
+    # duplication of test code in test_client.py due to missing
+    # functional build of go-sendxmpp for the Bullseye release (glibc
+    # mismatch in prebuilt package).
+    box: debian/bookworm64
     memory: 256
     cpus: 1
     provider_raw_config_args:
diff --git a/roles/xmpp_server/molecule/default/prepare.yml b/roles/xmpp_server/molecule/default/prepare.yml
index cddfe31b7ecbbd8f820eba30cee0bd60a8f4996a..62187af3f9d3e10025beb642832b9b024a2bb50f 100644
--- a/roles/xmpp_server/molecule/default/prepare.yml
+++ b/roles/xmpp_server/molecule/default/prepare.yml
@@ -183,7 +183,7 @@
 
     - name: Install console-based XMPP tool (for non-interactive testing)
       apt:
-        name: sendxmpp
+        name: go-sendxmpp
         state: present
 
     - name: Create dedicated group for testing
@@ -308,8 +308,10 @@
 
     - name: Install console-based XMPP tool (for non-interactive testing)
       apt:
-        name: sendxmpp
+        name: "{{ sendxmpp_package }}"
         state: present
+      vars:
+        sendxmpp_package: "{% if ansible_distribution_release == 'bullseye' %}sendxmpp{% else %}go-sendxmpp{% endif %}"
 
     - name: Deploy small Lua script for listing the enabled modules in Prosody
       copy:
diff --git a/roles/xmpp_server/molecule/default/tests/test_backup.py b/roles/xmpp_server/molecule/default/tests/test_backup.py
index 3c314f7b84133a18558d4770e2217b40bda5494d..1b27ff1455c629e956d212ce860611b18a0335bf 100644
--- a/roles/xmpp_server/molecule/default/tests/test_backup.py
+++ b/roles/xmpp_server/molecule/default/tests/test_backup.py
@@ -12,15 +12,30 @@ def test_backup(host):
     Tests if Prosody data directory is correctly backed-up.
     """
 
-    # Deliver a couple of messages in order to make sure the directory structure
-    # is created.
-    send = host.run("echo 'Hello' | sendxmpp --tls-ca-path /usr/local/share/ca-certificates/testca.crt "
-                    "-t -u jane.doe -p janepassword -j domain2:5222 jane.doe@domain2")
-    assert send.rc == 0
-
-    send = host.run("echo 'Hello' | sendxmpp --tls-ca-path /usr/local/share/ca-certificates/testca.crt "
-                    "-t -u mick.doe -p mickpassword -j domain3:5222 mick.doe@domain3")
-    assert send.rc == 0
+    distribution_release = host.ansible("setup")["ansible_facts"]["ansible_distribution_release"]
+
+    # Ugly, but functional for now.
+    if distribution_release == "bullseye":
+        # Deliver a couple of messages in order to make sure the directory structure
+        # is created.
+        send = host.run("echo 'Hello' | sendxmpp --tls-ca-path /usr/local/share/ca-certificates/testca.crt "
+                        "-t -u jane.doe -p janepassword -j domain2:5222 jane.doe@domain2")
+        assert send.rc == 0
+
+        send = host.run("echo 'Hello' | sendxmpp --tls-ca-path /usr/local/share/ca-certificates/testca.crt "
+                        "-t -u mick.doe -p mickpassword -j domain3:5222 mick.doe@domain3")
+        assert send.rc == 0
+    else:
+        send = host.run(f"echo 'Hello' | go-sendxmpp --debug "
+                        f"--username jane.doe@domain2 --password janepassword --jserver domain2:5222 "
+                        f"jane.doe@domain2")
+        assert send.rc == 0
+
+        send = host.run(f"echo 'Hello' | go-sendxmpp --debug "
+                        f"--username mick.doe@domain3 --password mickpassword --jserver domain3:5222 "
+                        f"mick.doe@domain3")
+        assert send.rc == 0
+
 
     with host.sudo():
 
diff --git a/roles/xmpp_server/molecule/default/tests/test_client.py b/roles/xmpp_server/molecule/default/tests/test_client.py
index c2b8cc3151d5b2edcd19c498d56bceeee790f0d0..372d5fd364ce7ba00e0436a7a7dd804f140298d3 100644
--- a/roles/xmpp_server/molecule/default/tests/test_client.py
+++ b/roles/xmpp_server/molecule/default/tests/test_client.py
@@ -34,13 +34,17 @@ def test_tls(host, username, password, domain):
     Tests if TLS works as expected.
     """
 
-    send = host.run(f"echo 'Hello' | sendxmpp --tls-ca-path /usr/local/share/ca-certificates/testca.crt "
-                    f"-t -u {username} -p {password} -j {domain}:5222 {username}@{domain}")
+    send = host.run(f"echo 'Hello' | go-sendxmpp --debug "
+                    f"--username {username}@{domain} --password {password} --jserver {domain}:5222 "
+                    f"{username}@{domain}")
     assert send.rc == 0
+    assert "<body>Hello</body>" in send.stderr
 
-    send = host.run(f"echo 'Hello' | sendxmpp --tls-ca-path /usr/local/share/ca-certificates/testca.crt "
-                    f"-e -u {username} -p {password} -j {domain}:5223 {username}@{domain}")
+    send = host.run(f"echo 'Hello' | go-sendxmpp --debug --tls "
+                    f"--username {username}@{domain} --password {password} --jserver {domain}:5223 "
+                    f"{username}@{domain}")
     assert send.rc == 0
+    assert "<body>Hello</body>" in send.stderr
 
 
 @pytest.mark.parametrize("username, password, domain", [
@@ -49,12 +53,15 @@ def test_tls(host, username, password, domain):
 ])
 def test_authentication_requires_tls(host, username, password, domain):
     """
-    Tests if authentication must be done over TLS.
+    Tests if STARTTLS is required.
     """
 
-    command = host.run(f"echo 'Hello' | sendxmpp --tls-ca-path /usr/local/share/ca-certificates/testca.crt "
-                       f"-u {username} -p {password} -j {domain}:5222 {username}@{domain} -d")
-    assert "<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'><required/></starttls>" in command.stderr
+    send = host.run(f"echo 'Hello' | go-sendxmpp --debug "
+                    f"--username {username}@{domain} --password {password} --jserver {domain}:5222 "
+                    f"{username}@{domain}")
+
+    assert send.rc == 0
+    assert "<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'><required/></starttls>" in send.stderr
 
 
 @pytest.mark.parametrize("username, password, domain", [
@@ -67,12 +74,14 @@ def test_authentication(host, username, password, domain):
     Tests if authentication works correctly.
     """
 
-    send = host.run(f"echo 'Hello' | sendxmpp --tls-ca-path /usr/local/share/ca-certificates/testca.crt "
-                    f"-t -u {username} -p {password} -j {domain}:5222 {username}@{domain}")
+    send = host.run(f"echo 'Hello' | go-sendxmpp --debug "
+                    f"--username {username}@{domain} --password {password} --jserver {domain}:5222 "
+                    f"{username}@{domain}")
     assert send.rc == 0
 
-    send = host.run(f"echo 'Hello' | sendxmpp --tls-ca-path /usr/local/share/ca-certificates/testca.crt "
-                    f"-e -u {username} -p {password} -j {domain}:5223 {username}@{domain}")
+    send = host.run(f"echo 'Hello' | go-sendxmpp --debug --tls "
+                    f"--username {username}@{domain} --password {password} --jserver {domain}:5223 "
+                    f"{username}@{domain}")
     assert send.rc == 0
 
 
@@ -86,7 +95,8 @@ def test_unauthorized_users_rejected(host, target_username, target_domain):
     group) are rejected from accessing the XMPP server.
     """
 
-    send = host.run(f"echo 'Hello' | sendxmpp --tls-ca-path /usr/local/share/ca-certificates/testca.crt "
-                    f"-t -u noxmpp -p noxmpppassword -j {target_domain}:5222 {target_username}@{target_domain}")
+    send = host.run(f"echo 'Hello' | go-sendxmpp --debug "
+                    f"--username noxmpp@{target_domain} --password noxmpppassword --jserver {target_domain}:5222 "
+                    f"{target_username}@{target_domain}")
     assert send.rc != 0
-    assert "Error 'AuthSend': error: not-authorized[?]" in send.stderr
+    assert "Unable to authorize you with the authentication credentials you've sent" in send.stderr