diff --git a/core/src/main/java/hudson/Functions.java b/core/src/main/java/hudson/Functions.java
index ac734f490eb5..6ebe09dd88ba 100644
--- a/core/src/main/java/hudson/Functions.java
+++ b/core/src/main/java/hudson/Functions.java
@@ -117,6 +117,9 @@
 import java.nio.charset.StandardCharsets;
 import java.text.DateFormat;
 import java.text.DecimalFormat;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatter;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Calendar;
@@ -235,7 +238,7 @@ public static String localDate(Date date) {
     }
 
     public static String rfc822Date(Calendar cal) {
-        return Util.RFC822_DATETIME_FORMATTER.format(cal.getTime());
+        return DateTimeFormatter.RFC_1123_DATE_TIME.format(ZonedDateTime.ofInstant(cal.toInstant(), ZoneId.systemDefault()));
     }
 
     /**
diff --git a/core/src/main/java/hudson/Util.java b/core/src/main/java/hudson/Util.java
index 24b04ce3085d..340a71706768 100644
--- a/core/src/main/java/hudson/Util.java
+++ b/core/src/main/java/hudson/Util.java
@@ -84,6 +84,7 @@
 import java.text.ParseException;
 import java.time.LocalDate;
 import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
 import java.time.temporal.ChronoUnit;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -1875,6 +1876,10 @@ public static void printRedirect(String contextPath, String redirectUrl, String
     public static final FastDateFormat XS_DATETIME_FORMATTER = FastDateFormat.getInstance("yyyy-MM-dd'T'HH:mm:ss'Z'", new SimpleTimeZone(0, "GMT"));
 
     // Note: RFC822 dates must not be localized!
+    /**
+     * @deprecated use {@link DateTimeFormatter#RFC_1123_DATE_TIME}
+     */
+    @Deprecated
     public static final FastDateFormat RFC822_DATETIME_FORMATTER
             = FastDateFormat.getInstance("EEE, dd MMM yyyy HH:mm:ss Z", Locale.US);