diff --git a/opendrop/__init__.py b/opendrop/__init__.py
index 8404244..2fc5d94 100644
--- a/opendrop/__init__.py
+++ b/opendrop/__init__.py
@@ -26,6 +26,6 @@ __version__ = "0.12.2"
 if platform.system() == "Darwin":
     dyld_path = os.environ.get("DYLD_LIBRARY_PATH", "")  # save old path
     archive_path = "/usr/local/opt/libarchive/lib"
-    os.environ["DYLD_LIBRARY_PATH"] = "{}:{}".format(dyld_path, archive_path)
+    os.environ["DYLD_LIBRARY_PATH"] = f"{dyld_path}:{archive_path}"
 
 logger = logging.getLogger(__name__)
diff --git a/opendrop/client.py b/opendrop/client.py
index f45c8ca..28adda7 100644
--- a/opendrop/client.py
+++ b/opendrop/client.py
@@ -97,7 +97,7 @@ class AirDropClient:
         logger.debug(f"Send {url} request")
 
         AirDropUtil.write_debug(
-            self.config, body, "send_{}_request.plist".format(url.lower().strip("/"))
+            self.config, body, f"send_{url.lower().strip('/')}_request.plist"
         )
 
         _headers = self._get_headers()
@@ -119,7 +119,7 @@ class AirDropClient:
         AirDropUtil.write_debug(
             self.config,
             response_bytes,
-            "send_{}_response.plist".format(url.lower().strip("/")),
+            f"send_{url.lower().strip('/')}_response.plist",
         )
 
         if http_resp.status != 200:
diff --git a/opendrop/config.py b/opendrop/config.py
index 1f0be42..91a49ef 100644
--- a/opendrop/config.py
+++ b/opendrop/config.py
@@ -81,9 +81,7 @@ class AirDropConfig:
         self.port = server_port
 
         if service_id is None:
-            service_id = "{0:0{1}x}".format(
-                random.randint(0, 0xFFFFFFFFFFFF), 12
-            )  # random 6-byte string in base16
+            service_id = f"{random.randint(0, 0xFFFFFFFFFFFF):012x}"  # random 6-byte string in base16
         self.service_id = service_id
 
         self.debug = debug
@@ -109,7 +107,7 @@ class AirDropConfig:
         self.root_ca_file = resource_filename("opendrop", "certs/apple_root_ca.pem")
         if not os.path.exists(self.root_ca_file):
             raise FileNotFoundError(
-                "Need Apple root CA certificate: {}".format(self.root_ca_file)
+                f"Need Apple root CA certificate: {self.root_ca_file}"
             )
 
         self.key_dir = os.path.join(self.airdrop_dir, "keys")
@@ -148,7 +146,7 @@ class AirDropConfig:
                 "-out",
                 "certificate.pem",
                 "-subj",
-                "/CN={}".format(self.computer_name),
+                f"/CN={self.computer_name}",
             ],
             cwd=self.key_dir,
             stdout=subprocess.PIPE,
diff --git a/opendrop/server.py b/opendrop/server.py
index e188e21..f6585df 100644
--- a/opendrop/server.py
+++ b/opendrop/server.py
@@ -54,14 +54,11 @@ class AirDropServer:
         if self.ip_addr is None:
             if self.config.interface == "awdl0":
                 raise RuntimeError(
-                    "Interface {} does not have an IPv6 address. "
-                    "Make sure that `owl` is running.".format(self.config.interface)
+                    f"Interface {self.config.interface} does not have an IPv6 address. Make sure that `owl` is running."
                 )
             else:
                 raise RuntimeError(
-                    "Interface {} does not have an IPv6 address".format(
-                        self.config.interface
-                    )
+                    f"Interface {self.config.interface} does not have an IPv6 address"
                 )
 
         self.Handler = AirDropServerHandler