diff --git a/mailnews/base/public/nsIMsgIncomingServer.idl b/mailnews/base/public/nsIMsgIncomingServer.idl
index 2e97e5c7f9e..7d29735ab53 100644
--- a/mailnews/base/public/nsIMsgIncomingServer.idl
+++ b/mailnews/base/public/nsIMsgIncomingServer.idl
@@ -82,6 +82,8 @@ interface nsIMsgIncomingServer : nsISupports {
   string getPasswordWithUI(in wstring aPromptString, in wstring aPromptTitle);
 
   /* should we download whole messages when biff goes off? */
+  /* in 4.x, this was "mail.pop3_gets_new_mail" for pop */
+  /* "mail.imap.new_mail_get_headers" for imap, and it was global.  in 5.x, it is per server */
   attribute boolean downloadOnBiff;
 
   /* should we biff the server? */
diff --git a/mailnews/base/src/nsMsgAccountManager.cpp b/mailnews/base/src/nsMsgAccountManager.cpp
index afeddb98235..37b25804cd3 100644
--- a/mailnews/base/src/nsMsgAccountManager.cpp
+++ b/mailnews/base/src/nsMsgAccountManager.cpp
@@ -129,6 +129,7 @@ static NS_DEFINE_CID(kMsgFolderCacheCID, NS_MSGFOLDERCACHE_CID);
 #define PREF_4X_MAIL_POP_PASSWORD "mail.pop_password"
 #define PREF_4X_NETWORK_HOSTS_POP_SERVER "network.hosts.pop_server"
 #define PREF_4X_MAIL_CHECK_NEW_MAIL "mail.check_new_mail"
+#define PREF_4X_MAIL_POP3_GETS_NEW_MAIL	"mail.pop3_gets_new_mail"
 #define PREF_4X_MAIL_CHECK_TIME "mail.check_time"
 #define PREF_4X_MAIL_LEAVE_ON_SERVER "mail.leave_on_server"
 #define PREF_4X_MAIL_DELETE_MAIL_LEFT_ON_SERVER "mail.delete_mail_left_on_server"
@@ -2276,6 +2277,7 @@ nsMsgAccountManager::MigrateOldMailPrefs(nsIMsgIncomingServer * server)
 #endif /* CAN_UPGRADE_4x_PASSWORDS */
   MIGRATE_SIMPLE_BOOL_PREF(PREF_4X_MAIL_CHECK_NEW_MAIL,server,SetDoBiff)
   MIGRATE_SIMPLE_INT_PREF(PREF_4X_MAIL_CHECK_TIME,server,SetBiffMinutes)
+  MIGRATE_SIMPLE_BOOL_PREF(PREF_4X_MAIL_POP3_GETS_NEW_MAIL,server,SetDownloadOnBiff)
 
   nsCOMPtr<nsIPop3IncomingServer> popServer;
   popServer = do_QueryInterface(server, &rv);
@@ -2481,6 +2483,9 @@ nsMsgAccountManager::MigrateOldImapPrefs(nsIMsgIncomingServer *server, const cha
   // upgrade the imap incoming server specific prefs
   MIGRATE_BOOL_PREF("mail.imap.server.%s.check_new_mail",hostAndPort,server,SetDoBiff)
   MIGRATE_INT_PREF("mail.imap.server.%s.check_time",hostAndPort,server,SetBiffMinutes)
+  // "mail.imap.new_mail_get_headers" was a global pref across all imap servers in 4.x
+  // in 5.0, it's per server
+  MIGRATE_BOOL_PREF("%s","mail.imap.new_mail_get_headers",server,SetDownloadOnBiff)
   MIGRATE_STR_PREF("mail.imap.server.%s.admin_url",hostAndPort,imapServer,SetAdminUrl)
   MIGRATE_INT_PREF("mail.imap.server.%s.capability",hostAndPort,imapServer,SetCapabilityPref)
   MIGRATE_BOOL_PREF("mail.imap.server.%s.cleanup_inbox_on_exit",hostAndPort,imapServer,SetCleanupInboxOnExit)
diff --git a/mailnews/base/util/nsMsgIncomingServer.cpp b/mailnews/base/util/nsMsgIncomingServer.cpp
index 67df55ef7ed..b9a3a74c56c 100644
--- a/mailnews/base/util/nsMsgIncomingServer.cpp
+++ b/mailnews/base/util/nsMsgIncomingServer.cpp
@@ -695,8 +695,7 @@ NS_IMPL_SERVERPREF_STR(nsMsgIncomingServer, PrefPassword, "password");
 NS_IMPL_SERVERPREF_BOOL(nsMsgIncomingServer, DoBiff, "check_new_mail");
 NS_IMPL_SERVERPREF_INT(nsMsgIncomingServer, BiffMinutes, "check_time");
 NS_IMPL_SERVERPREF_STR(nsMsgIncomingServer, Type, "type");
-
-/* what was this called in 4.x? */
-// pref("mail.pop3_gets_new_mail",				true);
-
+// in 4.x, this was "mail.pop3_gets_new_mail" for pop and 
+// "mail.imap.new_mail_get_headers" for imap (it was global)
+// in 5.0, this will be per server, and it will be "download_on_biff"
 NS_IMPL_SERVERPREF_BOOL(nsMsgIncomingServer, DownloadOnBiff, "download_on_biff");