diff --git a/src/os/unix/unix.cpp b/src/os/unix/unix.cpp
--- a/src/os/unix/unix.cpp
+++ b/src/os/unix/unix.cpp
@@ -164,7 +164,7 @@ static const char *convert_tofrom_fs(ico
 
 	iconv(convd, nullptr, nullptr, nullptr, nullptr);
 	if (iconv(convd, &inbuf, &inlen, &outbuf, &outlen) == (size_t)(-1)) {
-		DEBUG(misc, 0, "[iconv] error converting '%s'. Errno %d", name, errno);
+		Debug(misc, 0, "[iconv] error converting '{}'. Errno {}", name, errno);
 	}
 
 	*outbuf = '\0';
@@ -186,7 +186,7 @@ std::string OTTD2FS(const std::string &n
 		const char *env = GetLocalCode();
 		convd = iconv_open(env, INTERNALCODE);
 		if (convd == (iconv_t)(-1)) {
-			DEBUG(misc, 0, "[iconv] conversion from codeset '%s' to '%s' unsupported", INTERNALCODE, env);
+			Debug(misc, 0, "[iconv] conversion from codeset '{}' to '{}' unsupported", INTERNALCODE, env);
 			return name;
 		}
 	}
@@ -208,7 +208,7 @@ std::string FS2OTTD(const std::string &n
 		const char *env = GetLocalCode();
 		convd = iconv_open(INTERNALCODE, env);
 		if (convd == (iconv_t)(-1)) {
-			DEBUG(misc, 0, "[iconv] conversion from codeset '%s' to '%s' unsupported", env, INTERNALCODE);
+			Debug(misc, 0, "[iconv] conversion from codeset '{}' to '{}' unsupported", env, INTERNALCODE);
 			return name;
 		}
 	}
@@ -306,7 +306,7 @@ void OSOpenBrowser(const char *url)
 	args[1] = url;
 	args[2] = nullptr;
 	execvp(args[0], const_cast<char * const *>(args));
-	DEBUG(misc, 0, "Failed to open url: %s", url);
+	Debug(misc, 0, "Failed to open url: {}", url);
 	exit(0);
 }
 #endif /* __APPLE__ */