diff --git a/src/Http.cc b/src/Http.cc
index 5364c94..0018670 100644
--- a/src/Http.cc
+++ b/src/Http.cc
@@ -26,6 +26,7 @@
 #include <errno.h>
 #include <stdarg.h>
 #include <time.h>
+#include <limits.h>
 #include <fnmatch.h>
 #include <locale.h>
 #include <assert.h>
@@ -744,15 +745,10 @@ void Http::SendRequest(const char *connection,const char *f)
 		     (long long)((limit==FILE_END || limit>entity_size ? entity_size : limit)-1),
 		     (long long)entity_size);
       }
-      if(entity_date!=NO_DATE)
+      if((entity_date!=NO_DATE) && (entity_date>0L && entity_date<INT_MAX))
       {
-	 static const char weekday_names[][4]={
-	    "Sun","Mon","Tue","Wed","Thu","Fri","Sat"
-	 };
-	 const struct tm *t=gmtime(&entity_date);
-	 const char *d=xstring::format("%s, %2d %s %04d %02d:%02d:%02d GMT",
-	    weekday_names[t->tm_wday],t->tm_mday,month_names[t->tm_mon],
-	    t->tm_year+1900,t->tm_hour,t->tm_min,t->tm_sec);
+	 char d[256];
+	 strftime(d, sizeof(d), "%a, %d %b %H:%M:%S %Y GMT", gmtime(&entity_date));
 	 Send("Last-Modified: %s\r\n",d);
 	 Send("X-OC-MTime: %ld\r\n",(long)entity_date);	 // for OwnCloud
       }