diff --git a/check.py b/check.py
index 7630216..5d4c234 100755
--- a/check.py
+++ b/check.py
@@ -76,7 +76,6 @@ not_here_list = [
     "This page does not exist yet",
     "404 Not Found",
     "500 Internal Server Error",
-    "500: Internal Server Error",
     "Test Page for the Apache HTTP Server",
     "Site not found · GitHub Pages",
     "504: Gateway time-out",
@@ -186,24 +185,21 @@ class Conference:
     @property
     def url(self) -> str:
         """Conference URL."""
-        return self.build_url(year=self.year)
-
-    def build_url(self, year: int) -> str:
-        """Build conference URL."""
-        return self.src_url.format(year=year, two_digit_year=year % 2000)
+        return self.src_url.format(year=self.year)
 
     @property
     def past_url(self) -> str:
         """URL for previous year."""
-        return self.build_url(year=self.year - 1)
+        return self.src_url.format(year=self.year - 1)
 
     def check(self) -> tuple[bool, str, str | None]:
         """Check if conference is live."""
         no_dot = {"bsideskbh.dk", "pif.camp"}
-        url = self.url
-        session = s if all(hostname not in url for hostname in no_dot) else s_no_dot
+        session = (
+            s if all(hostname not in self.url for hostname in no_dot) else s_no_dot
+        )
         try:
-            r = session.get(url)
+            r = session.get(self.url)
         except requests.exceptions.ConnectionError:
             return (False, "connection refused", None)
 
@@ -232,7 +228,7 @@ class Conference:
 
     def check_web_site(self) -> bool:
         """Check if an individual web site is live."""
-        assert "{year}" in self.src_url or "{two_digit_year}" in self.src_url
+        assert "{year}" in self.src_url
         live, msg, redirect_to_url = self.check()
         if not live:
             return False